King v Western Sydney Local Health Network

The appellant, King, appealed to the Court of Appeal of New South Wales against a decision of the primary judge concerning a claim in negligence against the Western Sydney Local Health Network. The dispute arose from the alleged failure of the hospital to advise the appellant's mother of the availability and potential benefits of Varicella Zoster Immune Globulin (VZIG) and to offer its administration during her pregnancy, which the appellant contended led to her contracting chickenpox and consequently caused injury to the newborn child.

The Court of Appeal was required to determine whether the hospital had breached its duty of care to the newborn child by failing to advise and offer VZIG, and crucially, whether this breach constituted a necessary condition of the harm suffered by the child, as required by section 5D(1)(a) of the *Civil Liability Act 2002* (NSW). This involved assessing whether the administration of VZIG would have prevented the mother from developing chickenpox and thereby protected the child from injury. The court also considered whether, in light of the equivocal nature of the available medical literature and expert evidence regarding the efficacy of VZIG, the case qualified as an "exceptional case" under section 5D(2) of the *Civil Liability Act 2002* (NSW), allowing for a broader approach to causation.

The Court of Appeal, comprising Basten, Hoeben, and Ward JJA, found that the trial judge had not adopted an overly mechanistic approach to the causation issue and had appropriately considered the limitations and equivocal nature of the scientific evidence. The court acknowledged the conflicting expert opinions and the limitations of the available medical literature but concluded that the statistical probabilities, while not definitive, were insufficient to establish factual causation on the balance of probabilities. The court determined that the appellant had not discharged the onus of proving that the alleged breach was a necessary condition of the harm suffered.

Consequently, leave to appeal was granted, but the appeal itself was dismissed. The appellant was ordered to pay the respondent's costs of the appeal.