## Facts

- Thomas Allison, age 17 months, received Merck’s MMR II (measles, mumps, rubella) vaccine administered by the Clark County Health District.
- The Allisons alleged the vaccine caused Thomas to develop encephalitis, resulting in permanent injuries including blindness, deafness, cognitive impairment, and spastic contractures.
- Thomas asserted strict products liability claims against Merck as manufacturer.
- Jo Ann Allison asserted failure-to-warn claims related to the vaccine’s risks.
- Merck argued Restatement (Second) of Torts § 402A comment k (unavoidably unsafe products) barred strict liability for vaccines/prescription drugs and raised policy concerns about deterring vaccine development.
- The district court granted summary judgment for Merck and the Health District; the Allisons appealed.

## Issues

1. Whether comment k categorically bars strict products liability claims against a vaccine manufacturer, or whether strict liability may proceed upon proof of defect and causation.
2. Whether summary judgment was proper on claims that Merck failed to provide adequate warnings regarding vaccine risks.
3. Whether a county health district administering a vaccine is a seller/manufacturer subject to strict products liability.

## Decision

- The Nevada Supreme Court reversed summary judgment for Merck and remanded for trial on Thomas’s strict liability claim and Thomas’s and Ms. Allison’s failure-to-warn claims.
- The court held Merck was not categorically immune from strict liability under comment k; strict liability could apply if plaintiffs proved defect and causation.
- The court held the failure-to-warn claims against Merck presented triable factual issues.
- The court affirmed summary judgment for the Clark County Health District, concluding it was not a seller or manufacturer in the chain of distribution for strict products liability purposes.

## Legal Principles

- In Nevada strict products liability, a plaintiff must show injury caused by a defect in the product, and that the defect existed when the product left the defendant’s hands.
- A product is defective if it is dangerous because it fails to perform as reasonably expected in light of its nature and intended function.
- Restatement (Second) of Torts § 402A comment k does not provide blanket immunity for prescription drugs or vaccines; its application depends on product-specific facts, including proper preparation and the adequacy of warnings.
- Warning adequacy and causation in failure-to-warn claims commonly present fact questions not suitable for resolution on summary judgment when disputed.
- Strict products liability is limited to entities in the business of selling or distributing the product; a public health provider administering immunizations is not necessarily a seller/manufacturer for strict liability purposes.

## Conclusion

The court allowed strict liability and failure-to-warn claims against the vaccine manufacturer to proceed because comment k did not bar them as a matter of law and factual disputes remained, while it barred strict liability against the public health district because it was not a seller or manufacturer in the product’s distribution chain.


Allison v. Merck & Co., 110 Nev. 762, 878 P.2d 948 (Nev. 1994)