01:17 PM EDT, 03/31/2025 (MT Newswires) -- Shares of several vaccine companies were sharply lower on Monday after the top vaccine official at the US Food and Drug Administration resigned late Friday, blaming the current US Secretary of Health and Human Services for seeking "subservient confirmation of his misinformation and lies."

Dr. Peter Marks had led the FDA's Center for Biologics Evaluation and Research, choosing to step down after 13 years at the agency, which authorizes and monitors vaccine use, among other responsibilities. His expertise, however, ran counter to views and policies advocated by US Health Secretary Robert Kennedy Jr., a noted vaccine skeptic.

In his resignation letter, Marks cited data supporting the efficacy and safety of a two-dose vaccine given for measles, mumps and rubella and rejected assertions it was associated with several adverse side effects. "The vaccine very simply does not cause autism, nor is it associated with encephalitis or death," he said. "It does, however, protect against a potential devastating consequence of prior measles infection, subacute sclerosing panencephalitis, which is an untreatable, relentlessly progressive neurologic disorder."

Shares of Moderna ( MRNA ) , Novavax ( NVAX ) , BioNTech (BNTX) were down 9%, 7.6% and 6.9%, respectively. Pfizer ( PFE ) was off 1% while Inovio Pharmaceuticals ( INO ) was down 6.1% in recent trading.

Price: 28.34, Change: -2.79, Percent Change: -8.95