What happened

At about 14 weeks' pregnancy, the mother attended Blacktown Hospital soon after a child in her household was diagnosed with chickenpox and said she did not believe she was immune. Standard practice required advice about and an offer of VZIG within the post-exposure window, but it was not given; the mother contracted chickenpox and the child was born with foetal varicella syndrome causing severe physical and intellectual disability.

The issues

The issue was whether timely VZIG would probably have prevented the mother's infection or the child's syndrome, so that the breach was a necessary condition of the harm under s 5D(1)(a) of the Civil Liability Act 2002 (NSW). The evidentiary contest concerned the small observational studies, different German and Australian dosages, the natural non-infection rate, and the distinction between prevention and attenuation.

The court's decision

Hoeben JA and Ward JA held that the studies and expert evidence established a possibility, not probable causation for this mother and child. Basten JA dissented, considering the evidence and purpose of the treatment sufficient, but the majority dismissed the appeal and ordered the appellant to pay the respondent's appeal costs.

What this case shows

The decision emphasises that the existence of a medically recommended precaution does not itself prove legal causation when the precaution is omitted. Population statistics may be important circumstantial evidence, but their fit to the individual patient, dosage and outcome must be assessed with the rest of the evidence.

Why another case may differ

This was an appellate decision on 2002 VZIG practice and the limited studies and expert evidence tendered in this litigation. The majority did not determine exceptional causation under s 5D(2), because it had been expressly disclaimed at trial and was not properly raised as an appeal ground.

Applying it to your claim

Different facts, evidence or procedures, an appeal, or a change in the law may affect how this decision applies. This is general information, not a report of a case handled by Park & Co Lawyers.

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