Palmer v State of Western Australia (No 4)
[2020] FCA 1221
•25 August 2020
FEDERAL COURT OF AUSTRALIA
Palmer v State of Western Australia (No 4) [2020] FCA 1221
File number: QUD 183 of 2020 Judgment of: RANGIAH J Date of judgment: 25 August 2020 Catchwords: HIGH COURT AND FEDERAL COURT – remittal of part of proceeding from High Court of Australia pursuant to s 44 of the Judiciary Act 1903 (Cth) – reasonable need for and efficacy of Western Australia border restrictions – consideration of health risks to the Western Australian community – consideration of alternative measures to protect against risks – findings made Legislation: Constitution s 92
Evidence Act 1995 (Cth) s 140
Judiciary Act 1903 (Cth) s 44
Privacy Act 1988 (Cth) ss 4 and 94H
Emergency Management Act 2005 (WA)
Public Health Act 2005 (Qld)
Cases cited: APLA Ltd v Legal Services Commissioner (NSW) (2005) 224 CLR 322
Australian Broadcasting Corporation v Wing (2019) 271 FCR 632
Betfair Pty Ltd v Western Australia (2008) 234 CLR 418
Chamberlain v The Queen (No 2) (1984) 153 CLR 521
Clubb v Edwards (2019) 93 ALJR 448; (2019) HCA 11
Maloney v The Queen (2013) 252 CLR 168
McCloy v New South Wales (2015) 257 CLR 178
Palmer v State of Western Australia (No 3) [2020] FCA 1220
Re Day (2017) 91 ALJR 262; [2017] HCA 2
Thomas v Mowbray (2007) 233 CLR 307
Unions NSW v New South Wales (2019) 264 CLR 595
Division: General Division Registry: Queensland National Practice Area: Administrative and Constitutional Law and Human Rights Number of paragraphs: 367 Date of last submissions: 12 August 2020 (Respondents)
15 August 2020 (Applicants)Date of hearing: 22 July 2020 Counsel for the Applicants: Mr P Dunning QC with Mr R Scheelings and Mr P Ward Solicitor for the Applicants: Jonathan Shaw Solicitor Counsel for the Respondents: Mr J Thomson SC with Mr J Berson Solicitor for the Respondents: State Solicitor’s Office of Western Australia Counsel for Intervener (Solicitor-General of Commonwealth): Mr S Donaghue QC with Mr P Herzfeld, Mr M Hosking and Ms S Zeleznikow Solicitor for Intervener (Solicitor-General of Commonwealth): Australian Government Solicitor Counsel for Intervener (Attorney-General of Queensland): Mr GA Thompson QC with Ms F Nagorcka and Mr K Blore Solicitor for Intervener (Attorney-General of Queensland) Crown Law
Table of Corrections 3 September 2020 In lines 2, 4 and 5 of paragraph 360, the word “practical” has been changed to “ practicable”. 3 September 2020 In the heading preceding paragraph 361, the words “Assuming that a person enters Western Australia from:” has been added prior to subparagraph (a) of Issue 7. ORDERS
QUD 183 of 2020 BETWEEN: CLIVE FREDERICK PALMER
First Applicant
MINERALOGY PTY LTD (ACN 010 582 680)
Second Applicant
AND: STATE OF WESTERN AUSTRALIA
First Respondent
CHRISTOPHER JOHN DAWSON
Second Respondent
ORDER MADE BY:
RANGIAH J
DATE OF ORDER:
25 AUGUST 2020
THE COURT ORDERS THAT:
1.The costs of the remitted issue be reserved to the High Court of Australia.
Note: Entry of orders is dealt with in Rule 39.32 of the Federal Court Rules 2011.
REASONS FOR JUDGMENT
TABLE OF CONTENTS
The constitutional context and the pleadings
[14]
The issues
[22]
Onus and standard of proof
[37]
The agreed facts and the evidence
[42]
Areas of agreement and disagreement between the expert witnesses
[63]
The border restrictions under the Directions
[67]
Approach to assessment of risk
[70]
The potential public health consequences if COVID-19 were introduced into the Western Australian population
[82]
The utility and effectiveness of the border restrictions
[110]
The numbers of people entering Western Australia from interstate before and after the border restrictions
[119]
Dr Robertson
[123]
Associate Professor Lokuge
[129]
Professor Blakely
[136]
Professor Collignon
[137]
Associate Professor Senanayake
[148]
Conclusion upon the effectiveness of the border restrictions
[151]
The effectiveness of the border restrictions over the Common Measures
[158]
The probability of an infectious person entering Western Australia from interstate if the border restrictions were removed
[172]
Associate Professor Senanayake
[180]
Professor Blakely
[185]
Professor Collignon
[211]
Dr Robertson
[216]
Associate Professor Lokuge
[222]
Conclusions upon the probability of persons infected with COVID-19 entering Western Australia if the border restrictions were removed completely
[236]
Australia overall and Victoria
[255]
New South Wales
[264]
Tasmania
[270]
South Australia
[275]
Australian Capital Territory
[278]
Northern Territory
[282]
Queensland
[286]
The probability that an infectious person who enters Western Australia would transmit the disease, and the probability of such transmission causing an uncontrolled outbreak
[292]
The probability of persons infected with COVID-19 entering Western Australia under the present border restrictions
[303]
The effectiveness of alternative measures to reduce the probability of a person infected with COVID-19 entering the Western Australian population
[308]
The efficacy of the border restrictions compared to a targeted quarantine regime or a hotspot regime
[330]
The Agreed Statement of Issues
[351]
Issue 1: The extent to which the Directions contributed to preventing the spread of COVID-19 within Western Australia when they were introduced
[352]
Issue 2: The risk of an outbreak of COVID-19 occurring in Western Australia while the Directions remain in place
[353]
Issue 3: Whether the risk of a person from interstate crossing the Western Australian border while infected with SARS-CoV-2 is so low that it is a risk which may be disregarded
[354]
Issue 4: The risk of an outbreak of COVID-19 occurring in Western Australia if people from the following places are permitted to travel to Western Australia and no other changes are made to reduce the risk of the spread of COVID-19 from new arrivals
[355]
Issue 5: The risk of an outbreak of COVID-19 occurring in Western Australia if people from the places identified in paragraph 4 are permitted to travel to Western Australia and the following measures are implemented to reduce the risk of the spread of COVID-19 from new arrivals
[356]
Issue 6: Whether the measures of the kind identified in paragraphs 5.1, 5.2 and 5.3 would be reasonably available or as practicable as the Directions
[360]
Issue 7: Whether the risk of a person introducing SARS-CoV-2 is reduced by alternative measures
[361]
Issue 8: Whether there is an accepted body of epidemiological opinion that border measures are effective to limit the spread of infectious diseases
[362]
Findings upon further factual allegations pleaded
[363]
Summary
[366]
RANGIAH J:
On 11 March 2020, the World Health Organisation declared COVID-19 to be a pandemic. On 15 March 2020, the Minister for Emergency Services for Western Australia declared a state of emergency.
On 5 April 2020, the second respondent, the State Emergency Coordinator for Western Australia, issued the Quarantine (Closing the Border) Directions (WA). They have since been amended several times, most recently on 19 July 2020. I will refer to the current version as the “Directions”. The Directions were made pursuant to the Emergency Management Act 2005 (WA).
The Directions prohibit entry into Western Australia of persons other than those defined as “exempt travellers”.
On 25 May 2020, the applicants, Clive Frederick Palmer and Mineralogy Pty Ltd, commenced proceedings in the High Court of Australia seeking a declaration that the Emergency Management Act and/or the Directions are invalid, in whole or in part, on the basis that they contravene s 92 of the Constitution.
On 16 June 2020, the Chief Justice of the High Court made the following order:
Pursuant to section 44 of the Judiciary Act 1903 (Cth) so much of this matter as concerns the claim by the defendants of the reasonable need for and efficacy of the community isolation measures contained in the Quarantine (Closing the Border) Directions…made on 5 April 2020 be remitted to the Federal Court of Australia for hearing and determination.
From 27 to 31 July 2020, I conducted a hearing of the remitted issue. The applicants, the respondents and two interveners, the Attorney-General for the Commonwealth (Commonwealth) and the Attorney-General for Queensland (Queensland), actively participated in the hearing.
The respondents called two expert witnesses to give evidence, while the applicants called one expert witness and the Commonwealth called two. The Commonwealth supported the applicants’ case, and Queensland supported the respondents’ case. Each party cross-examined each of the witnesses and made opening and closing submissions.
On 2 August 2020, after the conclusion of the hearing, the Commonwealth notified the High Court that it was withdrawing from the proceeding. On 5 August 2020, the Commonwealth belatedly notified this Court of its withdrawal.
The respondents claimed that the Commonwealth was not entitled to withdraw without the leave of this Court, and that if the Commonwealth was given leave to withdraw, there should be a new hearing on the basis that they were prejudiced by the Commonwealth’s conduct. I held a hearing in respect of those claims on 7 August 2020. At that hearing, the applicants indicated that they relied upon the evidence that had been called and the submissions made by the Commonwealth. I have delivered separate reasons determining that the Commonwealth did not require leave from this Court to withdraw and that there should be no rehearing of the evidence: Palmer v State of Western Australia (No 3) [2020] FCA 1220.
Accordingly, I intend to decide the remitted issue on the basis of the whole of the evidence and the submissions. In view of the way the hearing was conducted, it remains convenient to distinguish between the evidence called by the applicants and the evidence called by the Commonwealth.
The remitted issue focuses on the determination of the factual matters involved in the respondents’ defence of the proceeding in the High Court. That defence involves a contention that the Community Isolation Measures, or border restrictions, contained in the Directions, are justified because:
(a)they are reasonably necessary for the protection of the Western Australian community against the health risks of COVID-19;
(b)they are reasonably appropriate and adapted to advance that object or purpose;
(c)there are no other equally effective means, which would impose a lesser burden on interstate trade, commerce and intercourse, available to achieve that object or purpose.
The remitted issue requires assessment of the risk of COVID-19 spreading into the Western Australian population were the border restrictions to be removed. That risk depends substantially upon the ability of public health authorities to control the outbreaks presently occurring in several States. However, the extent of the outbreaks is in a state of flux. While the parties agree that the facts are to be determined on the basis of the evidence presented at the hearing, there has necessarily been a time-lag between the hearing and the delivery of these reasons. These reasons, therefore, cannot take into account any factual developments since the hearing. That lends a degree of artificiality to these findings.
In order to give context to the remitted issue, it is necessary to consider the constitutional context in which that issue arises and the facts pleaded in the proceeding before the High Court.
The constitutional context and the pleadings
Section 92 of the Constitution provides that, “trade, commerce, and intercourse among the States…shall be absolutely free”.
The applicants allege in their Second Further Amended Statement of Claim that, in contravention of s 92, the Directions impose an effective burden on the freedom of intercourse, or impose an effective discriminatory burden with protectionist practical effect on the freedom of trade and commerce, among the Australian people in the several States.
In response, the respondents allege in para 47(c) of their Second Amended Defence that the relevant provisions of the Emergency Management Act and the Directions do not have the purpose of economically protecting Western Australia, but are for the legitimate purpose of protecting the population of Western Australia against the risks of an emergency situation.
The respondents plead in para 47(d) of their Second Amended Defence that the continuance in force of the Directions:
(iii)… is reasonably necessary to achieve, and is compatible with, the legitimate purpose of protecting the population of Western Australia against the health risks of COVID-19 where there are no other equally effective means available to achieve that purpose or object, but which impose a lesser burden on interstate trade or commerce;
(iv) does not prevent intercourse with the State of Western Australia among the States, except for the purpose of, and is reasonably necessary for, regulating or preserving the population of Western Australia against the health risks of COVID-19; and
(v)is reasonably appropriate and adapted to advance that purpose or object where there are no other equally effective means available to achieve that purpose or object, but which impose a lesser burden on interstate intercourse.
The respondents contend that whether a burden imposed upon the freedoms provided by either the trade or commerce limb or the intercourse limb of s 92 is constitutionally valid should be assessed in a similar way as is a burden imposed upon political communication under the test in McCloy v New South Wales (2015) 257 CLR 178 at [2]–[3] (French CJ, Kiefel, Bell and Keane JJ). A test of that kind appears to have been contemplated by the High Court in respect of the trade or commerce limb of s 92: see Betfair Pty Ltd v Western Australia (2008) 234 CLR 418 at [102]–[103] (Gleeson CJ, Gummow, Kirby, Hayne, Crennan and Kiefel JJ); Unions NSW v New South Wales (2019) 264 CLR 595 at [42] (Kiefel CJ, Bell and Keane JJ). A cognate approach has also been supported for the intercourse limb of s 92: see APLA Ltd v Legal Services Commissioner (NSW) (2005) 224 CLR 322 at [173]–[177] (Gummow J), [402], [408] and [421] (Hayne J).
Whether the respondents’ asserted analysis applies to either limb of s 92 is not a matter to be determined by this Court. It is sufficient to accept that this analysis is asserted by the respondents, and facts must be found upon that basis.
In para 15B(b) of their Amended Reply, the applicants plead that:
(a)the probability of a person infected with COVID-19 travelling to Western Australia is so small as to provide no reasonable justification for the continuance of the border restrictions;
(b)the relevant risk is the probability of uncontrolled and uncontrollable community transmission if the border restrictions were not in place; and the probability of such transmission is not sufficiently high to provide reasonable justification for the continuance of the border restrictions.
In para 20 of their Amended Reply, the applicants deny or do not admit the allegations in paras 47(d)(iii), (iv) and (v) of the Second Amended Defence.
The issues
Paragraphs 47(d)(iii), (iv) and (v) of the Second Amended Defence allege that the border restrictions imposed under the Directions are:
(a)reasonably necessary for the protection of the Western Australian population against the health risks of COVID-19; and
(b)reasonably appropriate and adapted to advance that purpose or object, in circumstances where there are no other equally effective means which impose a lesser burden on interstate trade, commerce and intercourse, available to achieve that purpose or object.
In these paragraphs, only “health risks” are raised in justification of the border restrictions. The parties submit that this Court ought not to consider other risks, such as economic or social risks. I will refrain from doing so.
The parties submit that this Court should not decide whether the Directions are in fact reasonably necessary for the protection of the Western Australian population, nor whether they are reasonably appropriate and adapted to advance that purpose or object, nor whether there are no other equally effective means which impose a lesser burden on interstate trade, commerce and intercourse, available to achieve that purpose or object. They submit that the purpose of the remitter is for the Federal Court to find the facts that will allow the High Court to determine these issues. I will refrain from deciding these matters. However, as there is no clear line of demarcation, some incursion may be unavoidable.
The parties agree that the respondents’ defence must be considered by reference to whether the border restrictions are currently justified, not whether they were justified when they were introduced.
There are several overlapping factual premises involved in paras 47(d)(iii), (iv) and (v) of the Second Amended Defence.
The first premise is that COVID-19 poses a substantial danger to the health of the Western Australian population.
The second is that the populations of other States and Territories are or may be infected with COVID-19, whereas the Western Australian population is not.
The third is that the border restrictions effectively protect the Western Australian population from COVID-19 by reducing the probability that infected people from other States and Territories will enter Western Australia.
The fourth is that, while there may be alternative methods available of reducing the probability that infected people will enter Western Australia, and which may impose a lesser burden on interstate trade, commerce and intercourse, they would be less effective, and inadequate, to protect the health of the Western Australian population.
The fifth is that if infected people did enter Western Australia, while there are measures that are or could be put in place to reduce the probability of the infection spreading into and amongst the population, which may impose a lesser burden on interstate trade, commerce and intercourse, they would be less effective, and inadequate.
It will be necessary to consider the applicants’ allegation that the probability of a person infected with COVID-19 travelling to Western Australia is so small as to provide no reasonable justification for the continuance of the border restrictions.
Further, the respondents plead that the risk is the risk of any community transmission of COVID-19, whereas the applicants plead that the relevant risk is the risk of uncontrolled and uncontrollable community transmission. It will be necessary to make findings relevant to both kinds of risk.
These issues make it necessary to determine:
(a)whether there is ongoing community transmission of COVID-19 in Australia;
(b)the public health consequences of persons infected with COVID-19 entering Western Australia and transmitting the virus;
(c)the extent of the contribution made by the border restrictions to reducing the probability of community transmission in Western Australia;
(d)the probability of COVID-19 being imported into Western Australia and community transmission occurring, including uncontrolled and uncontrollable community transmission, if the border restrictions were removed;
(e)the efficacy of measures other than the border restrictions in reducing the risk of introduction of COVID-19 into, and transmission within, Western Australia.
The parties and the interveners have agreed a Statement of Issues. The Statement of Issues largely, but not entirely, captures the facts which, in my opinion, need to be determined. In particular, the disputed issues do not deal expressly with the principles relevant to public health decision-making in the context of the pandemic, or the potential consequences of outbreaks of COVID-19.
I will proceed by, first, considering the onus and standard of proof; second, briefly describing the agreed facts and evidence and assessing the evidence of the expert witnesses; third, addressing the premises and factual issues I have identified; and, fourth, addressing the factual matters specifically pleaded in the Statement of Issues.
Onus and standard of proof
The respondents accept that they bear the ultimate onus of proof on the remitted issue.
However, the respondents submit that the facts required to be found by this Court are “constitutional facts”, and that concepts of legal onus and legal standards of proof are inapposite in respect of such facts. They rely upon Thomas v Mowbray (2007) 233 CLR 307 at [620]–[639] (Heydon J), Maloney v The Queen (2013) 252 CLR 168 at [355] (Gageler J) and Clubb v Edwards (2019) 93 ALJR 448; (2019) HCA 11 at [152] (Gageler J). They submit that, rather, the Court is required to be satisfied of the facts’ existence.
The applicants submit that the issues to be determined by this Court involve not only “constitutional facts”, but also “adjudicative facts”, in respect of which findings on the balance of probabilities should be made. They also submit that s 140 of the Evidence Act 1995 (Cth) applies to this proceeding and requires that findings of fact in civil proceedings be made on the balance of probabilities. They submit that in Re Day (2017) 91 ALJR 262; [2017] HCA 2, Gordon J at [14] indicated that facts would be found on the balance of probabilities, whether the facts were classifiable as “constitutional” or “adjudicative”.
The issue of the standard of proof in respect of fact finding in a case remitted for the making of findings of fact relevant to a constitutional issue is unsettled. It is unnecessary for me to enter upon the issue. That is because the respondents accept that the extent of the proof necessary to obtain the required satisfaction will be informed by the nature of the factual inquiry in question. They accept that, in particular, this is so where the High Court has determined that questions of fact are to be ascertained by judicial process: cf Re Day at [22]–[26]. The respondents accept that it is open to this Court to decide the “intermediate facts” applying a standard of the balance of probabilities. I propose to adopt that course.
The parties are in agreement that where an intermediate fact is essential to drawing the relevant inference for the existence of the ultimate fact, the Court requires the same standard of persuasion for the intermediate fact as it does for the ultimate fact: Chamberlain v The Queen (No 2) (1984) 153 CLR 521 at 538–539. However, they accept that where an intermediate fact is merely one circumstance, which is not of itself essential but which, together with other circumstantial evidence, would sustain the drawing of an inference as to an ultimate fact on the balance of probabilities, then it is not necessary that the intermediate fact itself be proven to that standard, provided the intermediate fact is not one the existence of which the Court doubts: Chamberlain at 537; Australian Broadcasting Corporation v Wing (2019) 271 FCR 632 at [134].
The agreed facts and the evidence
The parties have agreed upon a large number of facts. The agreed facts are set out in a Draft Consolidated Special Case. These reasons adopt the terminology used in, and assume familiarity with, the Draft Consolidated Special Case.
There were five expert witnesses who gave evidence. The experts, the date or dates of their reports and the parties by whom they were called, are:
·Dr Andrew Robertson — 24 June, 3 July 2020 (the respondents);
·Associate Professor Kamalini Lokuge — 26 June, 21 July 2020 (the respondents);
·Associate Professor Sanjaya Senanayake — 7 July 2020 (the applicants);
·Professor Peter Collignon — 7 July 2020 (the Commonwealth);
·Professor Tony Blakely — 8 July 2020 (the Commonwealth).
The dates of the reports assume some significance because some aspects of the reports have been overtaken by recent developments concerning outbreaks of COVID-19 in Australia. The reports were admitted into evidence without objection.
In addition, the experts prepared a joint report on 23 July 2020 following a conference between them, setting out their areas of agreement and disagreement.
The experts gave their evidence concurrently, with each witness being called in turn, but cross-examining counsel being able to ask questions of, not only the witness, but also the other experts.
I will summarise various aspects of the reports of the expert witnesses later in these reasons. I will give my general assessment of the witnesses at this stage.
Associate Professor Lokuge was a highly impressive witness. She is a public health physician and medical epidemiologist, with a doctorate in epidemiology. She leads the Humanitarian Health Research Initiative at the National Centre for Epidemiology and Population Health at the Australian National University Research School of Population Health. Associate Professor Lokuge has over two decades of experience as an epidemiologist investigating transmission and implementing control of infectious disease outbreaks and pandemics. She is a specialist in the control of infectious diseases.
Associate Professor Lokuge’s expertise covers front-line epidemiological, clinical and public health responses for controlling high-risk pathogen outbreaks. Her experience includes leading and participating in field-level responses to Ebola, Avian Influenza, Pandemic H1N1 Influenza and Lassa, in Africa, Asia and Australasia. She is a member of the National COVID-19 Health and Research Advisory Committee, an independent committee providing advice to the Chief Medical Officer of Australia. As part of her role on that committee, she chaired a working group which produced a report advising the Australian Government on priorities for preventing the resurgence of COVID-19 transmission. She is presently advising the Victorian health authorities in their attempts to control the current outbreak.
Associate Professor Lokuge demonstrated an impressive command of the relevant research and literature, both in her oral evidence and her reports. She was generally able to support the propositions she contended for by reference to data. Where the data did not allow conclusions to be reached, she was frank in so stating. Of the experts who gave evidence, Associate Professor Lokuge not only had the most comprehensive grasp of the academic research, but, by far, the greatest practical, front-line experience in the control of pandemics.
Associate Professor Lokuge also demonstrated an understanding of the principles involved in the containment of large-scale outbreaks of infectious diseases, in a way that some of the other experts did not. Her analysis took into account principles of risk management which balance the potential consequences or impact of an outbreak with the probability of the outbreak occurring. Associate Professor Lokuge, Dr Robertson and Professor Blakely were the only experts who expressly took into account the necessity for a precautionary approach in the management of the pandemic.
The applicants and the Commonwealth criticise Associate Professor Lokuge’s evidence on a number of grounds. A number of those grounds are unfounded. For example, the applicants’ criticism of examples given by Associate Professor Lokuge to illustrate the potential for large outbreaks despite an overall situation of good control, fails to recognise that the experts, citing some of her examples, unanimously agreed that rapid, uncontrolled transmission resulting from a single infected individual has occurred in multiple settings even where there is otherwise good surveillance/testing control. Some of the criticisms have some substance, as I will discuss in the course of these reasons, but that does not materially affect my overall view of her evidence.
I accept the opinions expressed by Associate Professor Lokuge, except to the extent I will indicate otherwise. I will more specifically consider the merits of her opinions on the disputed issues later in these reasons.
Dr Robertson has been the Chief Health Officer for Western Australia since June 2018. Since 2003, he has held several high-level positions involving disaster preparedness and management in the Western Australian Department of Health. He has specialist medical training and a masters’ degree in Public Health and Health Service Management. Dr Robertson’s recommendations were influential in the making of the Directions.
Dr Robertson’s expertise is upon general public health, rather than the specific area of transmission of infectious diseases. In his management of the pandemic, he has relied, at least in part, upon the advice of other experts. However, he has demonstrated considerable understanding of the practical implications of outbreaks of COVID-19 in Western Australia and the ability of the health authorities to deal with and control such outbreaks. Much of Dr Robertson’s evidence was consistent with that of Associate Professor Lokuge.
Associate Professor Senanayake is a Senior Staff Specialist in Infectious Diseases at the Canberra Hospital and an Associate Professor in the Australian National University Medical School. He is a specialist physician in the area of infectious diseases and has a masters’ degree in Applied Epidemiology. Associate Professor Senanayake has considerable experience in the treatment of infectious diseases, but has had little practical experience in the control of large-scale outbreaks. His record of research and publications in the area of pandemic control is also very limited.
Associate Professor Senanayake’s report was focused substantially upon the statistical probability of a person infected with COVID-19 entering Western Australia. He conceded under cross-examination that his calculations were estimations based upon average figures, and that average figures are not a proper basis for estimating inherently stochastic events such as COVID-19[1]. Associate Professor Senanayake also accepted that there were problems with a number of assumptions that he had made and that there was no evident explanation of the source of some figures he used[2]. He said that he suspected he had used the wrong version of an appendix to his report, and that had led to inaccuracies in the report[3]. In view of the concessions made by Associate Professor Senanayake, and the limits of his expertise and experience in the management of pandemics, I approach his evidence with caution. Where there is conflict between his opinions and those expressed by Associate Professor Lokuge, I prefer the opinions of Associate Professor Lokuge.
Professor Collignon is a specialist physician in infectious diseases and a specialist medical pathologist in the field of microbiology. He is a Senior Staff Specialist at ACT Pathology. He is also a Professor in the Australian National University Medical School. He has a doctorate in anti-microbial resistance and believes he is regarded as one of the world’s experts in the spread of resistant bacteria. He has over 30 years’ experience. Professor Collignon is a member of the Australian Government’s Infection Control Expert Group on COVID-19, which provides advice about the control of infections in hospitals and the community.
The respondents have not submitted that Professor Collignon was not qualified to give his opinion evidence. However, he was subjected to a vigorous cross-examination about the level of his expertise in respect of viral pandemics (when his primary area is antibiotic resistance), his absence of formal qualifications in epidemiology and the number of papers he has published concerning pandemics. It was also suggested that Professor Collignon was advocating for a position against the closure of State borders. While it was not improper for the respondents to cross-examine in this manner, in fairness to Professor Collignon, I will expressly state that I reject the attack upon his expertise and impartiality. The evidence he gave was within the bounds of his expertise. Further, while he had a firm position upon the issue of State-wide border restrictions, there is nothing to suggest that it was other than a genuinely held opinion.
Having said that, I do have reservations about some aspects of Professor Collignon’s evidence. Upon some important issues in his report and his oral evidence, he tended to fall back upon language such as “I consider”, “I believe” and “my view”. These expressions tended to mask the basis for his opinions, in contrast to Associate Professor Lokuge, whose reasoning tended to be more transparent. For example, Professor Collignon stated in his report that, “[I]n my view these outbreaks or clusters are better handled by targeted community and regional interventions rather than State-wide interventions”[4]. It may be inferred, from an earlier comment he had made, that this conclusion was based on economic, social and individual impacts[5]. Accordingly, it is not apparent that there is any epidemiological or public health basis for Professor Collignon’s opinion that outbreaks or clusters are better handled by targeted interventions than State-wide border closures. I do not think that Professor Collignon’s evidence exhibited the same level of transparency and clarity of Associate Professor Lokuge’s evidence, nor was it supported by the same level of detailed research. Nor does Professor Collignon have anything like the same level of experience in the practical containment of fast-spreading infectious diseases. Further, Professor Collignon did not display the same understanding of the principles of the management of a pandemic as Associate Professor Lokuge. Where there is conflict between the opinions of Professor Collignon and those expressed by Associate Professor Lokuge, I prefer the opinions of Associate Professor Lokuge.
Professor Blakely is an epidemiologist and public health medicine specialist at Melbourne University’s School of Population and Global Health. From 2010 to 2019, he directed the Burden of Disease Epidemiology, Equity and Cost Effectiveness Programme at the University of Otago. Prior to that, he conducted studies concerning smoking and cancer. He has medical qualifications, as well as a doctorate. His particular focus is on epidemiological and quantitative research methodologies.
Professor Blakely’s report states that it aims to quantify the probability of transmission of COVID-19 into Western Australia from other States and Territories if the border restrictions were removed. Professor Blakely expressed confidence in his methodology, while frankly and transparently acknowledging the uncertainties involved in a number of the assumptions underlying it. He acknowledged other limitations of his modelling, particularly that it does not account for intentional non-compliance with protective measures. Professor Blakely also acknowledged that while his modelling provides a tool that can be used as part of a suite of considerations when making decisions about border restrictions, it should not be used by itself to make such decisions. I accept that Professor Blakely’s model is a useful tool of analysis, subject to its inherent limitations which I will discuss. Apart from their differing opinions as to the usefulness of modelling, Professor Blakely’s opinions tended to align with those of Associate Professor Lokuge.
Areas of agreement and disagreement between the expert witnesses
The expert witnesses conferred on 22 and 23 July 2020. They produced a joint report in which they identified areas of their agreement and disagreement.
The experts summarised their areas of agreement as follows:
No. Question/Issues Areas in which the experts agree 1 Probability of an infection occurring in WA 1.1 What is the probability of an infected case of COVID-19 arriving at the border of Western Australia? In addressing this question we are referring only to domestic travellers and not to those arriving in Australia from international destinations.
We agree that given the existence of a strong surveillance/testing regime, if there have been no cases of community transmission (being where the source of the infection is unknown) for 28 days in the state of origin then that is as low risk a situation as can reasonably be hoped for.
We agree that the states and territories of Australia have strong surveillance/testing regimes, however, this is subject to change over time.
We agree that in terms of assessing risk factors associated with the probability of a Covid-19 case being imported into Western Australia, it is the community transmission numbers (where the source of the infection is unknown) that is most concerning.
… … … 2 Impact of importation to WA What are the possible impacts of the importation from within Australia of Covid-19 into Western Australia and what is the probability of those outcomes occurring? We are agreed that rapid uncontrolled transmission resulting from the introduction of a single infected individual to a community has been demonstrated to have occurred in multiple settings where there is otherwise good surveillance/testing control for example:
• South Korea
• Singapore
• Victoria
• NSW
• Tasmania3 Border restrictions 3.1 What is the value of border restrictions in preventing the transmission of Covid-19? We are agreed that border restrictions are important to ensure higher transmission risk populations do not spread Covid-19 to lower risk transmission populations. … … … 4. Other measures 4.1 What, if any, additional and/or alternative value is derived from border control measures over and above all non-border measures? For the purposes of this question, we agree that non-border measures include but are not limited to:
• intra-state movement restrictions;
• isolation;
• quarantine;
• PPE;
• good hand hygiene practices;
• physical distancing controls;
• restrictions on mass gatherings;
• appropriate surveillance (including testing and analysis of the data for targeted action);
• facilitating contact tracing; and
• support for communities and individuals to engage in the above mentioned practices.
We are agreed that all of the above “non-border” measures are useful and important in preventing the transmission of Covid-19.
We are also agreed that in many cases people do not follow the measures outlined above. .
There are differences between us as to what additional and/or alternative value state border control measures offer.
For the purposes of this question:
- quarantine is used to refer to the quarantine of individuals who might be incubating Covid-19 to prevent transmission.
- isolation is used to refer to the physical isolation of individuals who are infected with Covid-19 to prevent transmission
The experts set out their areas of disagreement by reference to a series of questions they posed. The questions are as follows:
1.1 What is the probability of an infected case of COVID-19 arriving at the border of Western Australia?
1.2 Having regard to question 1.1 above, is a quantitative and/or qualitative assessment of probability more useful in these circumstances?
2.1 What are the possible impacts of the importation from within Australia of COVID-19 into Western Australia and what is the probability of those outcomes occurring?
3.1 What is the value of border restrictions in preventing the transmission of COVID-19?
3.2 Are state borders a useful delineation between populations for the purposes of managing the transmission risk of COVID-19?
4.1 What, if any, additional and/or alternative value is derived from border control measures over and above all non-border measures?
I will address the experts’ opinions in respect of these areas of disagreement in the course of these reasons.
The border restrictions under the Directions
The Directions provide that a person must not enter Western Australia unless the person is an exempt traveller (cl 4). That restriction applies to all persons in the other States and Territories, regardless of whether they ordinarily reside in Western Australia.
There are 18 categories of “exempt traveller” (cl 27), which may be summarised as follows:
(a)certain Commonwealth and State government officials and military personnel (paras (a)-(f));
(b)persons responsible for provision of transport or freight and logistics services into or out of Western Australia, provided they remain for only so long as reasonably required (para (g));
(c)persons whose specialist skills are required for time-critical businesses or infrastructure (paras (h)-(i));
(d)persons whose presence is required for agriculture, food production or a primary industry (para (j));
(e)“FIFO” workers and their family members, who have undertaken a period of mandatory 14 day isolation (paras (k)-(l));
(f)emergency service workers (para (m));
(g)judicial officers and staff members of a court, tribunal or commission (para (n));
(h)persons who enter on medical, or specified compassionate grounds (paras (o)-(q));
(i)persons specifically authorised to enter on other grounds (para (r)).
The Directions also provide, broadly:
(a)an exempt traveller must comply with any specified terms or conditions — which may be imposed on a particular exempt traveller or persons in a category of exempt traveller (cll 27, 41);
(b)an exempt traveller must not enter Western Australia if the person has symptoms; has received notice that the person has a close contact who has tested positive; is awaiting a test result; or has received a positive test and has not been certified as having recovered (cll 5(a)-(d));
(c)an exempt traveller must not enter if the person has been in New South Wales or Victoria in the previous 14 days, unless:
(i)if the person falls within one or more of the categories in paras 27(a)-(g), the person complies with certain social-distancing, hygiene and mask-wearing precautions for 14 days;
(ii)if the person falls within paras 27(h)-(r), the person complies with terms and conditions (including any quarantine direction) authorised by the State Emergency Coordinator (cl 5(e));
(d)an authorised officer who is satisfied that a person has entered Western Australia contrary to cll 4 and 5, and that the person can leave Western Australia within a reasonable time and in an appropriate manner, must give the person a direction to leave (cl 9);
(e)a person who has entered Western Australia contrary to cll 4 and 5, and believes that they are unable to leave at all, or within a reasonable time, or in an appropriate manner, must request a quarantine direction (cl 7); and an authorised officer must give such a person a quarantine direction, whether or not requested by the person (cl 8);
(f)an authorised officer who gives a quarantine direction must give a direction to quarantine in a centre, unless a self-quarantine direction is given (cl 10);
(g)a self-quarantine direction may be given where an authorised officer is satisfied, inter alia, that a Western Australian resident has satisfactorily completed 14 days of supervised quarantine elsewhere in Australia (cl 11).
Approach to assessment of risk
The Directions state that their purpose is to limit the spread of COVID-19. They evidently aim to do so by limiting the numbers of people who enter Western Australia in order to reduce the probability that people infected with SARS-CoV-2 will enter.
As Associate Professor Lokuge points out, the most effective way for Western Australia to limit the risk to public health would be to close the borders to all travellers. However, for legal, economic and social reasons, exempt travellers are permitted to enter Western Australia. The formulation of the border restrictions plainly involves a balancing by the second respondent of public health risks against the other considerations. However, these reasons are only concerned with the public health risks posed by COVID-19.
The issues to be determined are concerned with the risk that a disease which is not presently amongst the Western Australian population, may enter the population in the future. There are many uncertainties about whether the disease might enter, the ways it might spread and the effectiveness of measures for the control of its entry and spread. The issues, accordingly, involve making predictions about what may happen in the future in hypothetical scenarios. What is known is that in the worst-case scenario, there may be catastrophic consequences for the population. These circumstances call for identification of principles that ought to be applied when making decisions about measures to protect against such risks to public health.
In his evidence, Dr Robertson referred to the “precautionary principle” and the need to take a precautionary approach. The application of these concepts in managing public health risks was explained by Associate Professor Lokuge in her report of 26 June 2020. She considers the probability of importation of COVID-19 into Western Australia from a State where community transmission cannot be known or quantified from reported data. It is her opinion that such uncertainty mandates the application of risk management principles including the “precautionary principle”[6]. Associate Professor Lokuge quotes from a paper entitled, “The Precautionary Principle: Protecting Public Health, the Environment and the Future of our Children”, published by the World Health Organisation[7]:
Public health is inherently about identifying and avoiding risks to the health of populations as well as in identifying and implementing positive interventions to improve population health. However, traditional public health interventions have generally focused on removing hazards that have already been identified. In contrast, the precautionary principle states that action should be taken to prevent harm ‘even if some cause and effect relationships are not fully established scientifically’. The precautionary principle therefore seeks to shift health and environmental policy from a strategy of ‘reaction’ to a strategy of ‘precaution’.
(Citations omitted.)
In her oral evidence, Associate Professor Lokuge explained that the precautionary principle indicates that action should be taken based upon an understanding of what might occur, because if authorities wait for clear evidence of its occurrence, it may be too late[8]. She said that in the context of a pandemic disease of high mortality, which is highly infectious and of rapid spread, the principle requires, from a public health perspective, implementation of all available and effective mitigation measures[9]. In the joint experts’ report, Associate Professor Lokuge states that this is exactly the situation that risk management approaches and the precautionary principle were developed to address — substantive uncertainty where important harms are plausible[10].
In her oral evidence, Associate Professor Lokuge indicated that the precautionary principle is an accepted principle of management of infectious diseases, saying that in all the outbreaks she has worked on, particularly those involving high risk pathogens, it is the guidance that she and her colleagues have used[11]. She considers that Western Australia has been applying that principle in its management of the pandemic[12].
I accept the evidence of Associate Professor Lokuge that the precautionary principle is an accepted principle of management of a pandemic which involves the potential for grave public health risks.
Dr Robertson’s evidence is consistent with Associate Professor Lokuge’s view. In addition, Professor Blakely expressly states that he recognises and supports the application of the precautionary principle in the management of the current pandemic[13]. Associate Professor Senanayake, commenting upon Associate Professor Lokuge’s report of 26 June 2020, agreed with the paragraph in which she indicated that the circumstances mandated the application of the precautionary principle[14].
A further principle emphasised by Dr Robertson and Associate Professor Lokuge is that public health risks are a function of probability and impact. In other words, the risks are measured, not merely by the probability that COVID-19 will be imported into the Western Australian population, but by the seriousness of health impacts for that population if that probability manifests[15].
The approaches described by Dr Robertson and Associate Professor Lokuge have the advantage of being logical. Although the probability that a particular health risk will manifest may be small, if its consequences are potentially catastrophic, a precautionary approach is required. This means, from a purely public health perspective, all reasonable and effective measures to mitigate that risk should ideally be put in place. This analysis, however, does not take into account the legal, economic and social considerations that must, in practice, be considered.
The adoption of these approaches to public health risks reflects, in the case of Dr Robertson, the perspective of a public official who is required to make recommendations and decisions for the practical protection of the health of a population. Their adoption reflects, in the case of Associate Professor Lokuge, the considerable practical experience of an expert used to providing advice on the management of pandemics where the consequences of wrong decisions may be severe. Professor Blakely’s frank acknowledgement of the considerable uncertainties involved in providing estimates of probabilities and that his estimates should not form the sole basis for decision-making, also reflects a precautionary approach.
In contrast, the evidence of other experts tended to underplay or overlook these approaches. For example, Associate Professor Senanayake said he was “optimistic” that an uncontrollable outbreak would not arise from the introduction of a single case[16]. Professor Collignon “preferred” a targeted quarantine approach over State-wide border restrictions without comparing their advantages and disadvantages from a public health perspective[17]. These opinions do not reflect a precautionary approach to public health risks.
The potential public health consequences if COVID-19 were introduced into the Western Australian population
I will commence by considering the second of the integers of risk to public health identified by Dr Robertson and Associate Professor Lokuge, namely the potential health impacts, or consequences, if COVID-19 were introduced into the Western Australian population.
If the disease were introduced, transmission within the community may be able to be controlled, as it was in some States and Territories, or it may be uncontrolled for at least some period of time, as appears to be the case in Victoria. By the time an outbreak is brought under control, there may be substantial health consequences.
First, COVID-19 has the capacity to kill. In Australia, the crude case fatality rate has been up to 1.4% (although the figure does not take into account cases not tested for) [18]. As at 27 July 2020, there were 161 deaths in Australia out of 14,935 confirmed cases[19]. The disease affects vulnerable groups with co-morbidities, such as people in aged care facilities and Indigenous communities, the most substantially. The Australian crude case fatality rate for those aged 65–79 has been 3.1%, and for those aged 80 and over has been 22.7%[20].
Second, COVID-19 can cause illness, the symptoms of which can include fever, coughing, sore throat, fatigue, shortness of breath, nasal congestion, headache, conjunctivitis, diarrhoea, loss of taste or smell, skin rash or discoloration of fingers or toes[21].
Third, about 13% of cases notified in Australia have required admission to hospital[22]. Dr Robertson estimates that for 100 new cases per day (or 1,000 active cases), 130 hospital beds and 25 ICU beds would be required, and 14 deaths expected; while for 500 new cases per day (or 5,000 active cases), 650 hospital beds and 124 ICU beds would be required, and 70 deaths expected. These numbers would remain within the capacity of the Western Australian health system to manage, but would substantially increase the burden upon the health system[23].
Fourth, there is presently no known vaccine or cure for COVID-19[24].
Fifth, SARS-CoV-2 is infectious during the incubation period (ie before symptoms first develop). Further, approximately 18–42% of cases remain asymptomatic, but are capable of transmitting the virus. There are others who remain only mildly symptomatic[25]. The median incubation time is 5–6 days (with a range between 1 to 14 days) [26]. A case is capable of transmitting the virus 1–3 days before exhibiting symptoms. Therefore, a person may spread the virus without the person knowing or suspecting that they have it[27].
Sixth, SARS-CoV-2 is highly infectious and is transmitted exponentially. If no measures are implemented to prevent spread of the virus, the growth rate (also known as the reproduction number) is approximately 2.3–2.5 (ie every infected person will infect on average 2.3–2.5 contacts) [28]. The expert witnesses agree that rapid uncontrolled transmission resulting from the introduction of a single infected individual to a community has been demonstrated to have occurred in multiple settings where there is otherwise good surveillance and testing control. So, for example, Associate Professor Senanayake comments that so-called “super-spreading events” have been associated with coronavirus infections such as SARS, MERS and COVID-19, and that this is a possible impact, but not a certain one, if a case is imported into Western Australia[29].
Seventh, testing for SARS-CoV-2 is imperfect. An infectious person can return a negative test[30].
Eighth, there are disincentives for testing, and the likelihood of each person undertaking testing is not equal. As Associate Professor Lokuge observes, whether a person is likely to submit to testing depends upon factors such as whether the person is a casual employee, has sick leave available and has access to Medicare, and upon the person’s personal background and experiences[31]. It can be inferred that some people who display symptoms or come into contact with a known carrier will not undergo testing and will continue to work and go about their routine activities unless and until they become seriously ill, and may, in the meantime, create chains of infection and clusters of COVID-19. As a result, the spread of the disease is stochastic[32]. As transmission relies on human interaction, the way such diseases move through a community reflects patterns of human interaction and disease control within that community, rather than an average across all of the population[33].
Associate Professor Lokuge estimates that the uptake of testing for people with symptoms consistent with COVID-19 is at most 50%[34]. Associate Professor Senanayake agrees[35]. I accept that this is a reasonable estimate.
Ninth, there is necessarily a lag time in identifying chains and clusters. Once an identified chain commences, or a cluster builds up, the hotspot can be locked down. As the median incubation period is 5–6 days, it will take at least a week for a hotspot to be identified, by which time a number of generations of transmission may have already occurred[36]. In that time, many people can be expected to have entered or left the hotspot, and potentially picked up and spread the infection outside of the identified hotspot.
Tenth, the effectiveness of Containment Measures depends upon the willingness and ability of people to comply with the measures. The disease is mainly spread by contact with infectious respiratory droplets or surfaces on which these droplets have gathered[37]. The prevention of transmission through such measures depends upon, for example, people keeping 1.5 metres away from each other, washing their hands regularly, increasing the frequency with which they clean surfaces, not gathering in large groups at family, religious and social events, and wearing a face mask. The experts agree that in many cases, people will not comply with these measures[38].
Eleventh, as COVID-19 has only recently emerged in the human population, the clinical, epidemiological and scientific knowledge base in respect of the disease is limited. There are a number of uncertainties about the disease, reflected in the qualifications placed upon many of the facts agreed in the Draft Consolidated Special Case. So, for example, the longer term health impacts of COVID-19 on those infected are not known, but the literature indicates it may include cardiac problems, coagulopathy, stroke, and, in children, multisystem inflammatory disorder[39]. There is also the possibility of airborne transmission of the virus, but more research is needed[40].
Associate Professor Lokuge is the only expert who has addressed the potential health impacts or consequences of the introduction of COVID-19 into the Western Australian population to a substantial extent.
In the joint experts’ report, Associate Professor Lokuge notes that all the experts agree that the most concerning form of transmission is community transmission which is undetected, and therefore uncontrolled[41]. That is a theme which recurs throughout the experts’ evidence. However, it is not the sole determinant of the risk of transmission, as there have been transmissions even when it is known that people are at substantial risk of being infectious: for example, there have been transmissions from people in quarantine.
In her report of 26 June 2020, Associate Professor Lokuge states that the impact depends upon the magnitude of transmission which results from a case, the severity of morbidity and mortality in those infected, and the response measures that are required to control further transmissions[42]. She observes that the importation of even a single case can result in a rapid increase in community transmission, with major consequences. She observes that systems for detection in Australia are comparatively strong, but not infallible[43].
Associate Professor Lokuge notes that if a case were imported into Western Australia and initiated community transmission, that would occur in a setting where COVID-19 has been eliminated. She states that large outbreaks are particularly likely if the disease is introduced to settings where containment measures have been relaxed and large gatherings are occurring. Of 1,100 individual “super-spreading” events which have been reported globally and catalogued, 480 of them involved over 100 cases[44].
Associate Professor Lokuge states that the impact depends upon the severity of the disease among those infected. It will have the highest morbidity and mortality in those who are older, obese, have chronic cardiac disease, chronic respiratory disease, neurological disease, liver disease or cancer. The introduction of disease into settings, such as residential care facilities, where such risk factors are more prevalent may have devastating consequences[45]. She states that if interstate importations result in community transmission in Western Australia, this will necessitate implementing stricter Community Isolation and Containment Measures, as are currently in place in Victoria[46].
To assess the severity of the impact, Associate Professor Lokuge applies a decision-tree algorithm from a 2009 paper entitled, “Assessing the Risk from Emerging Infections”, published in Epidemiology and Infection. Algorithms were developed to assess risks from emerging infectious diseases, and give a qualitative estimation of the probability and impact of introduction of the disease. Under an algorithm for, “Impact on Human Health: the Scale of Harm Caused by the Infectious Threat in Terms of Morbidity and Mortality”, the impact is characterised as “minimal”, “low”, “moderate”, “high” or “very high” based upon the answers to a series of questions[47]. In applying the decision-tree model to SARS-CoV-2, Associate Professor Lokuge answers the following questions, “Yes”:
·Is there human-to-human spread?
·Is the population susceptible?
·Does it cause severe disease in humans?
·Would a significant number of people be affected?
·Is it highly infectious to humans?
Associate Professor Lokuge gives a negative answer to the final question, “Are effective interventions [treatment or prophylaxis] available?”. On this basis, her opinion is that the impact of SARS-CoV-2 is categorised as “very high”, the highest possible categorisation[48].
Associate Professor Lokuge provided a supplementary report dated 21 July 2020. She notes that cases in the Victorian community from late May onwards have been linked to a few breaches, or perhaps a single breach, in quarantine measures. She states that the epidemiological links between the initial seeding events and cases of community transmission, were not recognised until genomic data was available several weeks later. This indicates that there must have been undetected community transmission occurring throughout that period between multiple community clusters. By the time new cases of locally-acquired disease had been identified in June 2020, levels of undetected community transmission were such that they resulted in a rapid increase in case numbers over the subsequent month, with 1,280 cases reported in the four days prior to her report. This was despite Victoria having the highest testing rates per capita and the highest levels of compliance with social distancing measures in Australia. This underlines that such measures are unlikely to control transmission within the community in Western Australia and, instead, if an importation initiates transmission, a return to much more stringent social distancing measures will be required[49]. I understand this to mean that a fuller range of Personal Isolation Measures, Community Isolation Measures and Containment Measures would be required.
Associate Professor Lokuge states that COVID-19 is not distributed evenly throughout the population. It is also highly clustered. In infectious disease modelling, the randomness in transmission is termed “stochasticity”, while the clustered and uneven distribution of cases is termed “heterogeneity”. As transmission relies on human interaction, the way such diseases move through a community reflects patterns of interaction and disease control within that community, rather than an average across all of the population. She states that even if testing and contact tracing levels are high across the population in general, as they are in Victoria, there are likely to be subgroups of the community with very different characteristics, who are both highly interconnected with each other and the wider community through family, work and social networks, and at the same time have lower engagement in response measures due to social, economic, cultural and demographic barriers to uptake. It is in such subgroups that disease would most widely circulate undetected when introduced. In the case of COVID-19, the period from initial introduction to multiple generations of unrecognised transmission is a few weeks at most in such a context. The characteristics of transmission in the early phases of the resurgence in Victoria reflects such a pattern[50].
Associate Professor Lokuge states that Western Australia has now returned to a level of social interaction similar to pre-COVID-19 levels and that very few, if any, in the Western Australian population would be immune to SARS-CoV-2. This means that the most likely reproduction number if a case of COVID-19 were introduced into the Western Australian community now would be similar to numbers seen early in the transmission of the virus globally, that is 2–2.5 people infected per case. She considers that the risk of large outbreaks from even a single importation is high in Western Australia, and higher than it was in Victoria when the current resurgence commenced[51]. It must be recognised that Western Australia is already at risk of importation even under the current border restrictions, but here Associate Professor Lokuge is talking about impact rather than probability.
Associate Professor Lokuge’s opinion is that the current resurgence of transmission in Victoria, and the seeding of transmissions into New South Wales from that resurgence, demonstrate the potential risks related to COVID-19 transmission. Even when testing, contact tracing and compliance with social distancing measures is high, rapid amplification can occur from one or a few cases, to the point where much more stringent measures preventing movement and interaction are required to slow the transmissions[52].
Dr Robertson considers that if cases of COVID-19 were imported into Western Australia, the exponential nature of the spread of the disease, and the possible failure to identify the disease immediately (although possibly mitigated by testing), would mean that the impact of the disease spread is serious, particularly if vulnerable communities, such as health care workers or Indigenous communities, were impacted. He states that as physical distancing decreases, the potential for outbreaks increases proportionately and the importation of one case could have more significant consequences[53]. He considers that “super-spreader” events would be of particular concern, as they can lead to rapid increase in both the initial number and subsequent growth of disease cases[54].
These aspects of the evidence of Associate Professor Lokuge and Dr Robertson have not been contradicted by the other experts. Professor Blakely acknowledges that the modelling he carried out does not take into account impact or consequences — it does not differentiate between an outbreak consisting of 5 cases or 500. I accept the opinions of Associate Professor Lokuge and Dr Robertson.
If COVID-19 is introduced into the Western Australian population, community transmission may be controlled or uncontrolled. Not all cases of community transmission will become uncontrolled, particularly as Australia has good systems of community controls and tracing, as the experts agreed. The initial outbreaks from February to April 2020 were brought under control in all States and Territories, except perhaps Victoria. However, if left uncontrolled for any substantial length of time, outbreaks will cause very severe consequences for the health of the Western Australian population. In the worst-case, the consequences could be catastrophic.
The utility and effectiveness of the border restrictions
The border restrictions aim to guard the Western Australian population from the importation of COVID-19 through the arrival of infected persons from other States and Territories. The utility of the border restrictions depends upon, first, whether there is such a risk of importation to guard against, and, second, whether they are effective to guard against such risk.
The last identified case of community transmission of SARS-CoV-2 in Western Australia was on 12 April 2020[55].
The parties have agreed in the Draft Consolidated Special Case that community transmission of any infectious disease can only be regarded as having ceased when two incubation periods have expired from the last confirmed case of community transmission within a community, although there remains a risk that there may be undetected disease within the community[56].
The expert witnesses agree that where there have been no reported cases of community transmission of COVID-19 for two incubation periods (28 days), the disease can be described as “eliminated”. The experts also agree that where there have been no reported cases of community transmission with an unknown source of infection for 28 days, that is “as low risk a situation as can reasonably be hoped for” [57].
The experts’ opinions do not, however, suggest that it will be certain that there are no ongoing community transmissions. First, the use of the expression “eliminated” may be misleading because, as the experts agreed, there may be underlying transmissions of asymptomatic or mildly symptomatic cases that have not been reported. Second, both the application of the 28 day period and the existence of risk more generally must be subject to the particular circumstances of, and changing circumstances within, a relevant State or Territory. For example, if the borders of a particular State have remained open, or have recently been opened to another State where there is ongoing community transmission, there must be a risk of as yet unidentified community transmission within the first State.
Since the Western Australian borders are not completely sealed to overseas and interstate travellers, and as the incubation period for COVID-19 is up to 14 days before symptoms are produced, it is possible that there may be unreported and undetected cases of community transmission in Western Australia. However, in the absence of any identified cases since 12 April 2020, it can be inferred that the probability of any present community transmission in Western Australia is negligible.
On 27 July 2020, data released by the Commonwealth Department of Health showed that there were 4,542 active cases in Victoria and 160 active cases in New South Wales. In both States, there was community transmission. I infer that in both States, there are cases where the source of the infection had not been identified because the total number of cases identified as “locally acquired — contact not identified” increased by 127 in Victoria and by 2 in New South Wales in the period from 24 to 27 July 2020[58].
I conclude that the probability of there being any community transmission of COVID-19 in Western Australia at present is negligible. However, there is ongoing community transmission, both from known and unknown sources, elsewhere in Australia. The experts specifically agree in their joint report that border restrictions are important to ensure higher transmission risk populations do not spread COVID-19 to lower transmission risk populations. Therefore, the border restrictions aim to guard the Western Australian population against an ongoing risk.
It is necessary to next consider the effectiveness of the border restrictions in guarding against the importation of COVID-19 cases from interstate.
The numbers of people entering Western Australia from interstate before and after the border restrictions
The respondents plead in para 39C of their Second Amended Defence that, on average, approximately 5,000 people per day entered Western Australia in 2019, and approximately 3,500–4,000 per day entered in March 2020. Those figures are the subject of non-admissions in the Amended Reply. However, the parties have proceeded on the basis that they are correct. For example, Associate Professor Senanayake and Associate Professor Lokuge were asked to assume that those were the numbers of arrivals from interstate.
These figures are not consistent with the figures agreed in the Draft Consolidated Special Case, which states that 2,995,133 passengers arrived in Western Australia from interstate between 1 January 2019 and 31 December 2019. That is an average of 8,205 arrivals per day. The parties have also agreed that 172,634 passengers arrived between 1 March 2020 and 31 March 2020. That is an average of 5,568 arrivals per day[59]. It has not been explained how the agreed figures were calculated, but it may be that they reflect the inclusion of arrivals from overseas. I will proceed on the basis that the figures of 5,000 per day in 2019 and 3,500–4,000 per day in March 2020 are correct because the hearing was conducted on that basis.
The parties also proceeded upon the basis that since the border restrictions were implemented, the number of people arriving in Western Australia from interstate has been, on average, about 470 per day (approximately 3,290 per week). Dr Robertson and Associate Professor Lokuge were asked to assume the correctness of the daily figure. Dr Robertson also said in oral evidence that he believed the weekly figure to be correct[60].
The experts disagree about the effectiveness of the border restrictions. I will consider their opinions upon this issue.
Dr Robertson
When Dr Robertson provided advice to the second respondent on 29 March 2020 about border restrictions, he stated that closing the Western Australian borders would have an impact on slowing the spread of COVID-19, but it would not reduce the risk significantly further than that achieved by measures already in place, such as isolation and restricting opening of retail outlets and mass gatherings[61].
In his first report of 24 June 2020, Dr Robertson expresses the opinion that the likelihood of importation of COVID-19 into Western Australia would be significantly higher if the Directions are revoked. He states that the likelihood is a function of the number of people crossing the border and the probability that those people are infected with the virus — the more people who come in from other States or Territories with community transmission, the greater the likelihood that the virus will be imported. Dr Robertson assesses the likelihood of importation of COVID-19 into Western Australia if the Directions are revoked as low (less than 10%) — that assessment being based upon the present low level of travellers coming into Western Australia. He considers that if the State were to move back towards its travel figures from six months ago, the risk would be higher. Dr Robertson considers that if the Directions are maintained, the likelihood of importation of the disease would be negligible. Although there remains a risk of both re-introduction of the disease and subsequent community transmission from exempt travellers, particularly those who are not subject to quarantine, Dr Robertson considers that with the Directions in place, the risk of disease re-introduction and community transmission in Western Australia is less than 1%[62].
As Dr Robertson acknowledged in re-examination, the percentage figures he gives are estimates rather than calculations. They are based upon his perceptions of risk, rather than reflective of any attempt at modelling or mathematical calculation[63]. I consider that the figures themselves should not be given any weight. Nevertheless, his impressionistic assessments have some value.
In his second report of 3 July 2020, Dr Robertson states that when he recommended the border restrictions, he noted weaknesses around people not self-isolating properly and essential workers not isolating at all. He came to the view that “closing” the borders would have the effect of slowing the spread of COVID-19. Dr Robertson took the view that the border restrictions would only be effective at that time because to be effective there had to be a differential risk across the country of developing the disease — if Western Australia had a similar rate of spread to the other States at that time, the closures would have far less impact[64].
In the joint experts’ report, Dr Robertson states that Containment and Personal Isolation Measures are likely to be adequate in most circumstances to prevent further community transmission, provided there is no re-introduction of the disease back into the community. He considers that border measures, through home or hotel quarantine of people crossing the border, will generally be required to prevent such re-introduction. He also considers that Containment and Personal Isolation Measures become less adequate over time, as people become less compliant with them. They also become less effective as restrictions are eased, with less physical distancing, increased mixing and less compliance with hygiene measures, leading to an increased potential for outbreaks; but also leading to a more normally functioning society with positive impacts on general health, through more available health services, and mental health stressors[65].
Dr Robertson considers that the United Kingdom provides a classic example of the consequences of not using border measures. The United Kingdom used Containment and Personal Isolation Measures, but did not lock their borders or impose quarantine until after the first wave, resulting in significantly increased case numbers and deaths[66].
Associate Professor Lokuge
In her report of 26 June 2020, Associate Professor Lokuge states that border measures are an accepted and essential component of the public health response to the control of infectious disease outbreaks. She states that the most effective way to control an infectious disease is through early and stringent border controls. She considers that this is particularly important for preventing cases from entering a region that is free of disease. She says that the most effective border measure would be to prevent people moving from regions with active community transmission into regions that do not have active community transmission[67].
In her first report, Associate Professor Lokuge, at one point, states that by “stringent” border measures, she means closing borders to all those outside the region[68], but later describes the Western Australian border restrictions (which allow exempt travellers) as “stringent”[69]. The applicants and the Commonwealth criticise that contradiction, but I consider that it is merely a slip or inconsistency in language, since Associate Professor Lokuge also expressly considers the current level of arrivals in her report. She states that the number of interstate visitors to Western Australia influences the probability of importation of COVID-19. She considers that the reduction in numbers of visitors to the present level decreases the probability of a case entering, on average, to 9–13% of what it would have been without the border restrictions (comparing the current figure of 470 arrivals per day to 3,500 to 5,000 per day before the pandemic)[70]. The average figures applied by Associate Professor Lokuge do not account for the stochastic nature of outbreaks of COVID-19, but are of some utility in assessing the impact of the border restrictions. The inference she draws that the probability has been substantially decreased is logical.
Associate Professor Lokuge considers that effective and early border closures would have prevented the resurgence in Victoria and its subsequent seeding into New South Wales. She notes that all other States and Territories have now closed their borders to Victoria, including New South Wales and the Australian Capital Territory, which had previously maintained open borders. She states that this is consistent with border controls being an essential component of public health measures for controlling COVID-19[71].
Associate Professor Lokuge states that in many settings where a single importation resulted in uncontrolled community transmission (such as Singapore and Melbourne), initial amplification occurred within subgroups that had lower engagement in control measures such as testing, community messaging, quarantine and isolation. The drivers for this included poverty, uncertain and casual work, language barriers, distrust of authorities, temporary visa status, overcrowded and unsanitary living conditions, and specific cultural and religious beliefs and behaviours. She notes that in modelling terms, this variation within subgroups is referred to as heterogeneity, and is why heterogeneity must be included in models of highly clustered infectious diseases such as COVID-19 if they are to be valid. She agrees that if all of these drivers were addressed and every person in the community had equal, equitable and high access to and uptake of all control measures, the risks of rapid, uncontrolled amplification of transmission would be greatly reduced. Until this is achieved, it remains her opinion that the border restrictions under the Directions provide the most immediate, effective and feasible strategy for preventing the impact of an importation[72].
In the joint experts’ report, Associate Professor Lokuge states that border measures are aimed at preventing infected individuals entering the community, whereas all other measures can only reduce the risk that infected individuals pass on disease to the community. She notes that, as all experts have agreed, even in settings where non-border measures have been implemented to a high degree, uncontrolled outbreaks can occur. She considers that border measures will always have additional value above and beyond other measures, as they are the only measures that can prevent entry of disease. She states that all places which have achieved good control of COVID-19 have had border controls as an integral part of their response. She therefore disagrees with Professor Collignon’s view that other measures can replace border measures[73].
It may be noted that Western Australia has measures similar to the measures described at 5.1.1-5.1.8 in place, except maximum group limits, which could be easily reintroduced. Therefore the part of the Issue at 5.2 amounts to a complex way of asking about the effect of changing the existing regime by replacing the existing border restrictions with a mandatory quarantining regime. I have dealt with this issue at [322]–[329].
Part of the Issue at 5.3 asks about the effect of changing the existing regime by replacing the existing border restrictions with a ban on arrivals from hotspots declared by Western Australia. I have dealt with this issue at [330]–[350].
Issue 6: Whether the measures of the kind identified in paragraphs 5.1, 5.2 and 5.3 would be reasonably available or as practicable as the Directions
The measures identified at 5.1, with the possible exception of compulsory use of the COVIDSafe application, are reasonably practicable since they are currently in place in Western Australia or could readily be put in place. The measure identified at 5.2 is not reasonably practicable for the reasons set out at [328]. The measure described at 5.3 is reasonably practicable, but less effective than State-wide or Territory-wide border restrictions for the reasons set out at [330]–[350].
Issue 7: Whether the risk of a person introducing SARS-CoV-2 is reduced by alternative measures
Assuming that a person enters Western Australia from:
(a) any or all of Queensland, South Australia, Tasmania, the Northern Territory and the Australian Capital Territory;
(b) New South Wales;
(c) Victoria, or
(d) any of these places,
whether the risk of such a person introducing SARS-CoV-2 into Western Australia and increasing the risk of morbidity and mortality in the Western Australian community is reduced (and to what extent) by the border entry restrictions contained in the Directions with the measures in paragraph 5.1 (to the extent implemented by Western Australia)), compared to:
7.1. where there are no border entry restrictions contained in the Directions but all of the measures in paragraph 5.1 are implemented (as proposed by the applicants or the Commonwealth); or
7.2. where there are no border entry restrictions contained in the Directions but all of the measures in paragraphs 5.1 and 5.2 are implemented (as proposed by the applicants or the Commonwealth); or
7.3. where there are no border entry restrictions contained in the Directions but all of the measures in paragraphs 5.1 and 5.3 are implemented (as proposed by the applicants or the Commonwealth).
Issue 7 appears to be similar to Issue 5, except that it seeks a breakdown of probability by reference to each State and Territory. I refer to [322]–[350].
Issue 8: Whether there is an accepted body of epidemiological opinion that border measures are effective to limit the spread of infectious diseases
Issue 8 should be answered “Yes”. I refer to [151].
Findings upon further factual allegations pleaded
In paras 47(d)(iii)–(v) of the Second Amended Defence, the respondents allege, in effect, that the Directions are justified and provide particulars of those paragraphs. The particulars which are relevant to the remitted issue are set out below:
aa.SARS-CoV-2 and COVID-19 are a new pathogen and disease, with the clinical and epidemiological knowledge of the virus and the disease, including the extent of its long-term effects, relatively uncertain;
a.the transmission of SARS-CoV-2 (which is the coronavirus which causes COVID-19) may occur without the awareness of a person that he or she is a Case who is capable of transmitting SARS-CoV-2, where that person is a Pre-Symptomatic Case, an Asymptomatic Case or a Symptomatic Case with only mild symptoms;
b.if there is community transmission of SARS-CoV-2, the natural growth rate for those infected, which is exponential, must be minimised through Personal Isolation Measures, Community Isolation Measures and Containment Measures;
c.the risk of community transmission of SARS-CoV-2 is substantially increased if Community Isolation Measures of the type contained in the Directions are removed, compared to the situation where both types of Isolation Measures and Containment Measures are implemented;
d.there are no known testing measures which by themselves are sufficient to prevent community transmission of SARS-CoV-2;
e.the ability to control community transmission of SARS-CoV-2 without re-introducing Community Isolation Measures of the type contained in the Directions depends upon the nature of the community transmission, and the number of Cases and their Contacts;
f.the consequences of community transmission of SARS-CoV-2 and the development of COVID-19 are substantial, including the increased risk of mortality, particularly for members of the population who are over 70 years of age, members of the population with pre-existing medical conditions, or members of the Aboriginal and Torres Strait Island population, and the risk that the hospital system in Western Australia will be unable to accommodate a substantial number of cases;
g.there is no known vaccine or treatment presently available to mitigate the risks of severe medical outcomes or mortality for a person who contracts COVID-19;
h.the time which it is necessary to continue with the Community Isolation Measures of the type contained in the Directions may be as little as 28 further days, or two incubation periods;
i.before Community Isolation Measures of the type contained in the Directions were implemented on 5 April 2020, Isolation Measures apart from the Directions were implemented;
j.the Community Isolation Measures contained in the Directions substantially reduced the risk of community transmission of SARS-CoV-2, and the risk of re-introduction of COVID-19 into the community;
k. no Isolation Measures, apart from those contained in the Directions, would be equally effective in reducing the risk of re-introduction of COVID-19 into the community of Western Australia and the risk of community transmission of SARS-CoV-2 within Western Australia, so as to prevent further community transmission from a Case which is infected and to prevent an increased risk of morbidity and mortality within the Western Australian community or population;
l.the easing or relaxation of the Community Isolation Measures contained in the Directions that apply to persons travelling from interstate can only occur without an increased risk of morbidity and mortality within the Western Australian community or population while there is no community transmission within other Australian States and Territories;
m.the easing or relaxation of applicable Containment Measures and Community Isolation Measures within Western Australia referred to in paragraphs 35, 37(a)-(b), 38(a) and 39B above, while there was no detected community transmission of SARS-CoV-2 within Western Australia from a local and unknown Case, could only occur without an increased risk of morbidity and mortality within the Western Australian community or population, while the Community Isolation Measures contained in the Directions were applicable;
…
I find that the particulars of paras 47(d)(iii)–(v) of the Second Amended Defence set out above have been proven.
In para 39C of their Second Amended Defence, the respondents plead a number of factual allegations concerning the effect of the Community Isolation Measures (the border restrictions) contained in the Directions. The allegations and my findings (in italics) in relation to them are set out below:
(a) The number of people arriving into Western Australia prior to announcement of the Community Isolation Measures of the type contained in the Directions was, on average, approximately 5,000 people per day in 2019 and 3,500 to 4,000 people per day in March 2020.
• These figures have not been agreed or proved by evidence, but I have accepted them to be correct given that the parties conducted the hearing on the basis that they were correct.
(b) There has been community transmission from an unknown Case in Australian States (apart from Western Australia) within the last 28 days prior to 15 June 2020.
• This has been proven in respect of Victoria and New South Wales.
(c) The Containment Measures, Personal Isolation Measures and Community Isolation Measures (apart from those contained in the Directions) were not wholly effective in reducing the rate of community transmission (ie the rate of infection of locally acquired cases from an unknown Case) as far as possible below a rate of 1.
• This allegation is contradicted by the agreement in the Draft Consolidated Special Case that, in Western Australia, the growth rate of confirmed cases of COVID-19 (covering internationally and locally acquired cases) was reduced to below 1 prior to the imposition of the Directions. To the extent that the allegation may be that the growth rate would have been even lower if the border restrictions had been introduced earlier, I do not accept the allegation. There were six reported cases of interstate transmissions to Western Australia prior to the introduction of the border restrictions and it is not apparent that they had any adverse impact on the growth rate.
(d)If the Community Isolation Measures contained in the Directions had not been implemented on 5 April 2020, there was a risk that Pre-symptomatic, Asymptomatic or Symptomatic Cases (including mildly Symptomatic Cases) would enter the Western Australian community or population without being aware that they were infected with SARS-CoV-2, and/or without being detected as a Case, and would become the source of community transmission from an unknown Case.
• I find that it has been proven that there was such a risk.
(e)The risk of a Case with SARS-CoV-2 entering the Western Australian community or population unknowingly and/or undetected referred to in the last subparagraph was substantially greater than the risk posed once the Community Isolation Measures in the Directions were implemented.
• I find that this allegation has been proven.
(f)The Community Isolation Measures contained in the Directions substantially reduced the risk of re-introduction of COVID-19 into the community and also substantially reduced the risk of community transmission of SARS-CoV-2, from an unknown Case entering the Western Australian community or population from interstate unknowingly and/or undetected, in the circumstances stated in the next paragraph.
• I find that this allegation has been proven.
(g)The Containment Measures, Personal Isolation Measures and Community Isolation Measures, apart from those contained in the Directions, are unlikely to be adequate to contain the transmission of COVID-19 to a particular Case from a local and unknown Case of SARS-CoV-2, so as to prevent further community transmission from that particular Case and to prevent an increased risk of morbidity and mortality within the Western Australian community or population.
• I find that the combination of the border restrictions contained in the Directions and the other measures described (the Common Measures) have been effective to prevent further community transmission in Western Australia, and are likely to continue to be successful in the future. The use of one set of these measures alone is unlikely to do so. It cannot be determined whether in respect of “a particular Case”, the Common Measures are unlikely to be inadequate because of the stochastic nature of transmission of the disease and chance.
(h)No Isolation Measures, apart from those contained in the Directions, would be equally effective in reducing the risk of community transmission of SARS-CoV-2 within Western Australia, and in reducing the risk of re-introduction of COVID-19 into the community of Western Australia, so as to prevent further community transmission from the Case which is infected and to prevent an increased risk of morbidity and mortality within the Western Australian community or population.
• I find that this allegation has been proven.
(i)The easing or relaxation of the Community Isolation Measures contained in the Directions that apply to persons travelling from interstate can only occur without an increased risk of morbidity and mortality within the Western Australian community or population while there is no community transmission within other Australian States and Territories.
• I do not accept that this allegation has been proven. The experts conclude that the risk is higher from some States and Territories than others, and that the disease can be considered to be “eliminated” when there has been no community transmission from an unknown source for 28 days. It may therefore be possible to ease the border restrictions with some States and Territories without a significantly increased risk of morbidity and mortality in the Western Australian population while there is ongoing community transmission within other States and Territories.
(j)The easing or relaxation of applicable Containment Measures, Personal Isolation Measures and Community Isolation Measures within Western Australia referred to in paragraphs 35, 37(a)-(b), 38(a) and 39B above, while there was no detected community transmission of SARS-CoV-2 within Western Australia from a local and unknown Case, could only occur without an increased risk of morbidity and mortality within the Western Australian community or population, while the Community Isolation Measures contained in the Directions were applicable.
• I accept that this allegation has been proven.
Summary
In summary, the findings I have made include the following:
·The risk to the health of the Western Australian population is a function of two factors: the probability that COVID-19 would be imported into the population; and the seriousness of the consequences if it were imported.
·The existing border restrictions do not eliminate the potential for importation of COVID-19 from other States or Territories, since they allow “exempt travellers” to enter Western Australia. However, the restrictions have reduced the numbers of people entering from interstate to approximately 470 people per day, compared to approximately 5,000 per day in 2019 and approximately 3,500–4,000 per day in March 2020 (that is, to 9% – 13% of the previous level).
·The border restrictions have been effective to a very substantial extent to reduce the probability of COVID-19 being imported into Western Australia from interstate.
·The probability of persons infected with COVID-19 entering Western Australia in a hypothetical scenario where the border restrictions are removed cannot be accurately quantified because of the substantial uncertainties involved in predicting all the relevant factors. The uncertainties include the absolute numbers of persons in other States who may be infected, the behavioural characteristics of the disease and the unpredictable behaviour of people who are or may be infected. For example, it is difficult to predict what the numbers of infected people will be in Victoria and New South Wales in the short to medium term when those numbers are in a state of flux. Attempting to predict the numbers of people who would travel when infected involves predicting factors such as the numbers who would be asymptomatic or pre-symptomatic when travelling. The unpredictable aspects of human behaviour include the proportion of people who would engage in risky behaviour by travelling when symptomatic, and the proportion who would undergo testing if they exhibit symptoms.
·However, based on the evidence currently available, the following qualitative assessments of the probability that persons infected with COVID-19 would enter Western Australia if the border restrictions were completely removed have been made:
Australia as a whole — high.
Victoria — high.
New South Wales — moderate.
Queensland — uncertain (due to the recent introduction of the disease).
South Australia, the Australian Capital Territory, the Northern Territory — low.
Tasmania — very low.·If persons enter the Western Australian community while infectious, there would be a high probability that the virus would be transmitted into the Western Australian population; and at least a moderate probability that there would be uncontrolled outbreaks.
·If there were uncontrolled outbreaks in Western Australia, the consequences would include the risk of death and hospitalisation (particularly for vulnerable groups, such as elderly and Indigenous people). In the worst-case scenario, the health consequences could be catastrophic.
·Western Australia has not had any cases of community transmission since 12 April 2020 as a result of the combination of the border restrictions and the range of other measures in place including isolation, testing, social distancing and hygiene measures and requirements for some exempt travellers to wear masks or be quarantined.
·If the current border restrictions were replaced by mandatory hotel quarantining for all entrants to Western Australia for 14 days, Western Australia could not safely manage the number of people in hotel quarantine.
·If the border restrictions were replaced by a suite of measures including exit and entry screening, mandatory wearing of face masks on aeroplanes, PCR testing on the second and twelfth days after entry and mandatory wearing of face masks for fourteen days after entry, they would be less effective than the border restrictions in preventing the importation of COVID-19.
·If the border restrictions were replaced by that suite of measures plus a “hotspot” regime, involving either quarantining or banning persons entering from designated hotspots, they would be less effective than the border measures in preventing the importation of COVID-19.
·In view of the uncertainties involved in determining the probability that COVID-19 would be imported into Western Australia from elsewhere in Australia, and the potentially serious consequences if it were imported, a precautionary approach should be taken to decision-making about the measures required for the protection of the community.
The costs of the remitted issue will be reserved to the High Court.
I certify that the preceding three hundred and sixty-seven (367) numbered paragraphs are a true copy of the Reasons for Judgment of the Honourable Justice Rangiah. Associate:
Dated: 25 August 2020
ENDNOTES
[1] Transcript 28 July 2020 p 207 ll 10-29
[2] Transcript 28 July 2020 p 209 l 38 – p 215 l 34
[3] Transcript 29 July 2020 p 249 ll 9-13
[4] Expert Report of Professor Collignon, Court Book Tab 38 p 541 at [51]
[5] Transcript 29 July 2020 p 268 l 46 – p 269 l 8
[6] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 467 at [3.2.8]
[7] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 467 at [3.2.8]
[8] Transcript 28 July 2020 p 187 ll 14-23
[9] Transcript 28 July 2020 p 189 ll 6-19
[10] Joint Experts’ Report, Court Book Tab 43 p 700 at [1.2]
[11] Transcript 28 July 2020 p 187 ll 25-29
[12] Transcript 28 July 2020 p 191 ll 9-17
[13]Report of Professor Blakely Identifying Differences of Opinion Between the Experts, Court Book Tab 41 p 681
[14] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 505
[15] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 466 at [3.2.3]
[16] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 497 at [23]
[17] Expert Report of Professor Collignon, Court Book Tab 38 p 541 at [52]
[18] Draft Consolidated Special Case p 4 at [9]
[19] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3552
[20] Draft Consolidated Special Case p 4 at [10]–[11]
[21] Draft Consolidated Special Case p 7 at [21(e)]
[22] Draft Consolidated Special Case p 5 at [17]
[23] Supplementary Expert Report of Dr Robertson, Court Book Tab 36 p 428 at [4.3.8]
[24] Draft Consolidated Special Case p 5 at [14]
[25] Draft Consolidated Special Case p 7 at [21(b)]-[21(c)]
[26] Draft Consolidated Special Case p 4 at [8]
[27] Draft Consolidated Special Case p 7 at [21(a)]
[28] Draft Consolidated Special Case p 9 at [23(a)]
[29] Joint Experts’ Report, Court Book Tab 43 p 701 at [2]
[30] Draft Consolidated Special Case, Court Book Tab 44 p 715 at [19]
[31] Transcript 28 July 2020 p 183 ll 9-17
[32] Transcript 28 July 2020 p 207 l 40 - p 209 l 26; Transcript 29 July 2020 p 313 l 45 - p 314 l 37
[33] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 686 at [14]
[34] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 456 at [2.3.8.3]
[35] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 504
[36] Draft Consolidated Special Case p 4 at [8]
[37] Draft Consolidated Special Case p 3 at [4]
[38] Joint Experts’ Report, Court Book Tab 43 p 705 at [4.1]
[39] Draft Consolidated Special Case pp 5-6 at [13], [19]
[40] Draft Consolidated Special Case p 3 at [4]
[41] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[42] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 469 at [3.2.15]
[43] Expert Report of Associate Professor Lokuge, Court Book Tab 35 pp 469-470 at [3.2.17]
[44] Expert Report of Associate Professor Lokuge, Court Book Tab 35 pp 469-470 at [3.2.17]
[45] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 470 at [3.2.19]
[46] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 471 at [3.2.21]
[47] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 479
[48] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 471 at [3.2.22]
[49] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 685 at [10]–[11]
[50] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 pp 686-687 at [14]
[51] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 687 at [16]
[52] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 690 at [24]
[53] Expert Report of Dr Robertson, Court Book Tab 34 p 426 at [3.4.1]–[3.4.2]
[54] Joint Experts’ Report, Court Book Tab 43 pp 701-702 at [2]
[55] Draft Consolidated Special Case p 13 at [30]
[56] Draft Consolidated Special Case p 10 at [23(i)]-[23(j)]
[57] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[58]Daily Epidemiology Update as at 1500h, 24 July 2020 p 2; Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[59] Draft Consolidated Special Case p 59 at [133]
[60] Transcript 27 July 2020 p 76 ll 3-7
[61] Supplementary Expert Report of Dr Robertson, Court Book Tab 36 p 489
[62] Expert Report of Dr Robertson, Court Book Tab 34 pp 424-425 at [3.2]–[3.3]
[63] Transcript 28 July 2020 p 124 ll 36-47
[64] Supplementary Expert Report of Dr Robertson, Court Book Tab 36 p 486 at [3]–[4]
[65] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[66] Joint Experts’ Report, Court Book Tab 43 p 705 at [4.1]
[67] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 457 at [2.3.9.1.1]–[2.3.9.1.2]
[68] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 457 at [2.3.9.1.3]
[69] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 471 at [3.2.24]
[70] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 468 at [3.2.10]
[71] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 690 at [24]
[72] Joint Experts’ Report, Court Book Tab 43 pp 701-702 at [2]
[73] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[74] Joint Experts’ Report, Court Book Tab 43 p 705 at [4.1]
[75] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[76] Joint Experts’ Report, Court Book Tab 43 pp 702, 705 at [3.1] and [4.1]
[77] Expert Report of Professor Collignon, Court Book Tab 38 p 535 at [31]
[78] Expert Report of Professor Collignon, Court Book Tab 38 p 536 at [32]
[79] Expert Report of Professor Collignon, Court Book Tab 38 pp 536-537 at [33]–[34]
[80] Expert Report of Professor Collignon, Court Book Tab 38 p 537 at [35]-[36]
[81] Expert Report of Professor Collignon, Court Book Tab 38 p 537 at [37]
[82] Expert Report of Professor Collignon, Court Book Tab 38 p 537 at [38]
[83] Joint Experts’ Report, Court Book Tab 43 p 701 at [2]
[84] Joint Experts’ Report, Court Book Tab 43 p 704 at [4.1]
[85] Transcript 29 July 2020 p 282 ll 1-2
[86] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 501 at [41]
[87] Joint Experts’ Report, Court Book Tab 43 p 702 at [3.1]
[88] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[89] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[90] Expert Report of Associate Professor Senanayake, Court Book Tab 37 pp 501-502 at [43].
[91] Draft Consolidated Special Case p 68 at [170]
[92] Expert Report of Professor Collignon, Court Book Tab 38 p 537 at [36]
[93] Joint Experts’ Report, Court Book Tab 43 p 702 at [3.1].
[94] Draft Consolidated Special Case pp 34, 50 at [70], [103]
[95] Transcript 27 July 2020 p 81 ll 27-32
[96] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[97] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 468 at [3.2.10]
[98] Expert Report of Professor Collignon, Court Book Tab 38 p 535 at [31]
[99]Draft Consolidated Special Case pp 69-79 at [172]-[196]
[100] Joint Experts’ Report, Court Book Tab 43 p 704 at [4.1]
[101] Joint Experts’ Report, Court Book Tab 43 p 702 at [3.1]
[102] Joint Experts’ Report, Court Book Tab 43 p 701 at [2]
[103] Draft Consolidated Special Case pp 74-78 at [186]-[193]
[104] Joint Experts’ Report, Court Book Tab 43 pp 704-705 at [4.1]
[105] Expert Report of Professor Collignon, Court Book Tab 38 p 539 at [47]
[106] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 493 at [2] and [7]
[107] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 495 at [13]
[108] Expert Report of Associate Professor Senanayake, Court Book Tab 37 p 497 at [23]
[109] Transcript 28 July 2020 p 213 l 3 – p 214 l 41
[110] Transcript 28 July 2020 p 219 ll 10-45
[111] Transcript 28 July 2020 p 205 l 10 - p 206 l 5
[112] Transcript 28 July 2020 p 207 l 40 – p 209 l 26
[113] Transcript 28 July 2020 p 233 ll 14-21
[114] Expert Report of Professor Blakely, Court Book Tab 40 pp 602-603
[115] Expert Report of Professor Blakely, Court Book Tab 40 p 603
[116] Expert Report of Professor Blakely, Court Book Tab 40 p 604
[117] Expert Report of Professor Blakely, Court Book Tab 40 p 604
[118] Expert Report of Professor Blakely, Court Book Tab 40 p 606
[119] Expert Report of Professor Blakely, Court Book Tab 40 p 607
[120] Expert Report of Professor Blakely, Court Book Tab 40 p 609
[121] Expert Report of Professor Blakely, Court Book Tab 40 p 609
[122] Expert Report of Professor Blakely, Court Book Tab 40 pp 609-611 at [3.5]
[123] Expert Report of Professor Blakely, Court Book Tab 40 p 611
[124]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using up to date Victorian data
[125]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using up to date Victorian data
[126]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using updated NSW data to 23 July
[127]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using updated NSW data to 23 July
[128] Joint Experts’ Report, Court Book Tab 43 pp 699-700 at [1.1]
[129] Expert Report of Professor Blakely, Court Book Tab 40 p 602
[130] Transcript 29 July 2020 p 380 l 26 – p 381 l 8
[131] Transcript 28 July 2020 p 107 ll 8-30
[132] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 456 at [2.3.8.3]
[133] Transcript 28 July 2020 p 106 l 1
[134] Transcript 28 July 2020 p 112 ll 37-38
[135] Transcript 28 July 2020 p 107 l 43 – p 108 l 2.
[136] Transcript 28 July 2020 p 114 ll 10-13
[137] Transcript 29 July 2020 p 401 ll 22-27
[138] Expert Report of Professor Collignon, Court Book Tab 38 p 541 at [31]
[139] Joint Experts’ Report, Court Book Tab 43 p 700 at [1.2]
[140] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[141] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[142] Expert Report of Professor Collignon, Court Book Tab 38 p 541 at [51]
[143] Expert Report of Dr Robertson, Court Book Tab 34 pp 424-425 at [3.2.1]-[3.3.2]
[144] Expert Report of Dr Robertson, Court Book Tab 34 p 425 at [3.3.3]-[3.3.5]
[145] Transcript 27 July 2020 p 73 ll 31-34
[146] Transcript 28 July 2020 p 103 l 46 – p 104 l 4
[147] Transcript 28 July 2020 p 124 ll 36-47
[148] Expert Report of Dr Robertson, Court Book Tab 34 p 425 at [3.3.5]
[149] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[150] Joint Experts’ Report, Court Book Tab 43 pp 700-701 at [1.2]
[151] Transcript 27 July 2020 p 39 ll 22-26
[152] Transcript 27 July 2020 p 85 ll 28-34
[153] Transcript 27 July 2020 p 87 l 3 – p 88 l 8
[154] Joint Experts’ Report, Court Book Tab 43 p 700 at [1.2]
[155] Transcript 28 July 2020 p 135 l 31 – p 136 l 5
[156] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 466 at [3.2.5]
[157] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 467 at [3.2.8]
[158] Expert Report of Associate Professor Lokuge, Court Book Tab 35 pp 468-469 at [3.2.11]-[3.2.12]
[159] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 469 at [3.2.13]
[160] Expert Report of Associate Professor Lokuge, Court Book Tab 35 pp 471-472 at [3.2.24]
[161] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 473 at [4.1.1]
[162] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 688 at [18]-[19]
[163] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 689 at [23]
[164] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[165] Joint Experts’ Report, Court Book Tab 43 pp 699-700 at [1.1]
[166] Joint Experts’ Report, Court Book Tab 43 pp 702-703 at [3.1]
[167] Expert Report of Professor Blakely, Court Book Tab 40 p 603
[168] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[169] Expert Report of Dr Robertson, Court Book Tab 34 p 425 at [3.3.2]-[3.3.5]
[170] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 471 at [3.2.24]
[171] Transcript 28 July 2020 p 173 l 8 – p 174 l 39
[172]Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3552; Daily Epidemiology Update as at 1500h, 24 July 2020
[173] Transcript 28 July 2020 p 138 ll 44-47
[174]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using up to date Victorian data
[175] Supplementary Expert Report of Associate Professor Lokuge, Court Book Tab 42 p 687 at [16]
[176] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[177] Stay Safe Directions (No 6) (Vic), Court Book Tab 198 p 2375
[178] Stay at Home Directions (Restricted Areas) (No 3) (Vic), Court Book Tab 197 p 2362
[179]Draft Consolidated Special Case pp 57-58 at [128]
[180] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[181] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3552
[182]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using updated NSW data to 23 July
[183] Transcript 29 July 2020 p 407 ll 28-31
[184] Transcript 29 July 2020 p 355 ll 31-40
[185] Draft Consolidated Special Case p 67 at [163]-[166]
[186] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[187] Transcript 28 July 2020 p 123 ll 14-21
[188] Draft Consolidated Special Case p 62 at [146]
[189] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[190] Draft Consolidated Special Case p 64 at [152]
[191] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[192] Draft Consolidated Special Case p 68 at [170]-[171]
[193] Daily Epidemiology Update as at 1500h, 27 July 2020, Court Book Tab 258 p 3554
[194] Transcript 27 July 2020 p 87 l 3 – p 88 l 8
[195] Draft Consolidated Special Case p 67 at [159]-[161]
[196] COVID-19 Epidemiology Report 20 (to 5 July 2020), Court Book Tab 91 p 1495
[197] Draft Consolidated Special Case pp 60-61 at [138]-[140]
[198] Public Health Alert: Three new COVID-19 cases, Court Book Tab 257
[199] Transcript 29 July 2020 p 349 l 4 – p 351 l 5
[200] Joint Experts’ Report, Court Book Tab 43 p 701 at [2]
[201] Expert Report of Associate Professor Lokuge, Court Book Tab 35 p 473 at [4.3.2]
[202] Expert Report of Professor Blakely, Court Book Tab 40 p 609 at [3.4.2]
[203] Joint Experts’ Report, Court Book Tab 43 p 701 at [2]
[204] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[205] Expert Report of Dr Robertson, Court Book Tab 34 p 425 at [3.3.1]
[206] Draft Consolidated Special Case p 92 at [218]
[207] Transcript 27 July 2020 p 82 ll 14-15
[208] Draft Consolidated Special Case p 91 at [212]
[209] Transcript 29 July 2020 p 285 ll 9-16
[210]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using up to date Victorian data
[211]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using up to date Victorian data
[212]Exhibit 7 – Table 3: Average or expected years and months to outbreak, and average monthly probability (and %) of outbreak per month – Using updated NSW data to 23 July
[213] Draft Consolidated Special Case p 79 at [196]
[214] Expert Report of Professor Blakely, Court Book Tab 40 p 619
[215] Expert Report of Professor Blakely, Court Book Tab 40 p 611
[216] Expert Report of Associate Professor Lokuge, Court Book Tab 35 pp 468-469 at [3.2.11]-[3.2.12]
[217] Transcript 27 July 2020 p 82 ll 14-15
[218] Draft Consolidated Special Case p 94 at [227]
[219] Draft Consolidated Special Case p 94 at [219]
[220] Expert Report of Professor Collignon, Court Book Tab 38 p 541 at [52]
[221] Expert Report of Professor Collignon, Court Book Tab 38 p 542 at [53]
[222] Transcript 29 July 2020 p 269 ll 1-13
[223] Joint Experts’ Report, Court Book Tab 43 p 699 at [1.1]
[224] Draft Consolidated Special Case p 4 at [8]
[225] Transcript 29 July 2020 p 392 ll 19-26
[226] Joint Experts’ Report, Court Book Tab 43 p 704 at [3.2]
[227] Transcript 28 July 2020 p 120 ll 25-31
[228] Transcript 28 July 2020 p 179 ll 24-30
[229] Transcript 28 July 2020 p 224 l 13 – p 225 l 1
[230] Transcript 29 July 2020 p 318 l 28 – p 319 l 16
[231]Transcript 28 July 2020 p 234 ll 4-7; Transcript 29 July 2020 p 350 ll 23-24; Transcript 29 July 2020 p 406 ll 31-35.
[232] Public Health Alert: Three new COVID-19 cases, Court Book Tab 257
[233] Joint Experts’ Report, Court Book Tab 43 pp 703-704 at [3.2]
[234] Joint Experts’ Report, Court Book Tab 43 pp 703-704 at [3.2]
[235] Transcript 28 July 2020 p 113 ll 1-10
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