Chickenpox Vaccine MDL Grows

On November 10, a complaint was filed against Merck & Co. Inc. and its parent company McKesson Corp. regarding product liability concerning a chickenpox vaccine. The case is part of the larger, ongoing Zostavax Products Liability multidistrict litigation (MDL). This complaint was filed in the Eastern District of Pennsylvania and alleged that Merck knowingly produced, marketed, and distributed a vaccine that was inherently flawed and with misleading suggested treatment plans.

The Varicella-Zoster virus, more commonly known as chickenpox, has noted morbidity and mortality in its initial infection, which typically happens as a child or young adult. However, any person who has contracted the virus is at risk for a later reactivation of the virus. This later reactivation of the virus, known as herpes-zoster, can result in painful blisters and neuralgia on the nerves located proximate to the site.

Zostavax is a live-attenuated virus vaccine, which means that a live, but weakened form of the virus is used to create an immune response in the recipient. As the virus is live in these injections, there is a possibility for the virus to be either “over-attenuated” and not induce a sufficient immune response, or under-attenuated and serve as a vector for infection. The complaint alleged that the Zostavax vaccine was subject to both reactions, especially if the vial in question was an older product, where the efficacy of the vaccine is liable to dwindle. The complaint averred that Merck failed to warn of either complication, as well as promoted a product that was inherently liable to manufacturing defects. 

The complaint lists 7 causes of action, including negligence, product liability in design and manufacturing defect, product liability in failure to warn, breach of express warranty, breach of implied warranty, unjust enrichment, and loss of consortium. The plaintiffs are being represented by Marc J. Bern & Partners LLP.