Center for Biologics Evaluation and Research (CBER) chief Vinay Prasad has come under scrutiny after an internal FDA memo linked the deaths of 10 children to COVID-19 vaccinations. The memo, which was leaked and published by The Washington Post, did not provide specific evidence to support this claim.
The statement had immediate effects on the stock market, particularly impacting mRNA vaccine producers Moderna and BioNTech. Moderna’s shares fell 7% to $24.16 at Monday’s close, adding to a year-to-date decline of over 40%. BioNTech’s shares also dropped by 3.9% to $98.44.
Experts have raised concerns about Prasad’s lack of transparency and his reliance on the Vaccine Adverse Events Reporting System (VAERS), a public system for reporting side effects after vaccinations. Peter Lurie, president of the Center for Science in the Public Interest and former associate commissioner at the FDA, told BioSpace: “After years of working at the FDA I’ve never seen a memo like that. It’s a screed that veers into things of no clear relevance whatsoever.”
Prasad stated in his six-page memo titled “Deaths in children due to COVID-19 vaccines and CBER’s path forward” that an investigation found cases in VAERS but did not provide further data or details about which manufacturers were involved or when the deaths occurred. He also announced intentions to change regulations not only for COVID-19 vaccines but also influenza and pneumonia vaccines.
Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, commented: “He gives you no data to support that surprising assertion; he just puts it out there. When you make a sensational claim like that, a frightening claim like that, at the very least, you owe it to the public to provide the evidence.”
Lurie questioned whether proper criteria were used in evaluating VAERS reports and noted these reports are unsubstantiated until investigated further by authorities such as OBPV or individuals who submitted them.
In his memo, Prasad criticized observational cohort studies and case control data used in vaccine approvals as having “notorious methdologic [sic] biases,” without specifying what those biases were. Lurie responded: “Those data are usually from sources—clinical trials, people presenting to emergency rooms, etc.—considered preferable to VAERS reports.” He added that Prasad's approach elevates lower-quality data over established clinical trial results.
Dorit Reiss, professor of law at UC Law San Francisco, said: “He’s expressly not doing cost/benefit analysis, even though it’s his job. This is a bad way to do policy” demonstrating Prasad's lack of regulatory experience. She added: “Essentially, he’s announcing that he’s making changes by fiat.”
The vaccine industry has faced challenges throughout 2025 with increased anti-vaccine rhetoric since Robert F. Kennedy Jr.’s appointment as Secretary of Health and Human Services earlier this year and subsequent changes within advisory committees such as those at CDC and FDA approval guidelines being narrowed. Major companies including Pfizer, Merck, GSK and Sanofi have reported declining sales amid shifting public sentiment toward vaccines.
William Blair analysts wrote Monday: “We see further headwinds towards [Moderna’s] declining COVID-19 franchise alongside further negative sentiment that this memo and subsequent actions may generate.” They highlighted concerns regarding potential new scrutiny from CBER on Moderna's updated trivalent flu vaccine following Phase III trial results showing improved efficacy but higher rates of non-serious adverse events such as fatigue and headaches.
The situation remains fluid as both regulators and industry stakeholders await more detailed information from CBER regarding any future policy changes affecting vaccine development or approval processes.
