The plaintiffs contracted HIV from blood and blood products supplied by the Canadian Red Cross Society (CRCS) between 1983 and 1985.
They alleged the CRCS was negligent in its blood donor screening procedures.
The trial judge found the CRCS breached its standard of care by using a 'good health' questionnaire rather than symptom-specific questions, but dismissed one plaintiff's action for failing to prove causation.
The Court of Appeal upheld the negligence findings and reversed the causation dismissal by applying a presumptive causal link.
The Supreme Court of Canada dismissed the CRCS's appeals, holding that while the Court of Appeal erred in applying a presumptive causal link, causation was established under the material contribution test because the CRCS's failure to implement adequate screening measures materially contributed to the plaintiffs contracting HIV.