Allison Gatlin, Investors Business Daily, Dec 1, 2025
Now, Vinay Prasad, who heads up the Center for Biologics Evaluation and Research, wants a stricter review and approval process for vaccines. CBER is the FDA branch in charge of, among other products, vaccines. According to media reports and analysts, Prasad issued a memo describing a link between Covid shots and death due to myocarditis, or swelling in the heart.
"Fear, confusion, but no data," Leerink Partners analyst Mani Foroohar said in a report. Prasad "sent an inflammatory internal email highlighting findings of death due to COVID vaccines in children and (vowed) to make substantial changes to the vaccine approval and monitoring framework."
Moderna stock tumbled more 7%, ending the regular session at 24.16, while shares of Pfizer (PFE) and BioNTech (BNTX) skidded a respective 1.8% and 5.6%. Moderna makes the messenger RNA-based Covid vaccines Spikevax and mNexspike, while Pfizer and BioNTech partner on mRNA-based Comirnaty.
Shares of Dynavax Technologies (DVAX), which is testing an oral Covid vaccine, tumbled 5.8%. Novavax (NVAX), another Covid vaccine maker, slumped 5.1%. Dynavax's and Novavax's approaches don't use mRNA technology, which some studies have suggested heightens the risk of myocarditis in boys and young men.
So far, just 5.8% of children and 13.8% of adults in the U.S. have received Covid vaccines this season, William Blair analyst Myles Minter said in a report. This comes after the Centers for Disease Control and Prevention ended the universal recommendation for Covid vaccines.
"If new regulatory restrictions were to be implemented in the higher myocarditis risk population, we see further headwinds toward the company's declining COVID-19 franchise alongside further negative sentiment that this memo and subsequent actions may generation," Minter said.
The memo outlines an analysis from the Office of Biostatistics and Pharmacovigilance. OBPV examined 96 deaths between 2021 and 2024 following vaccination. No fewer than 10 were related to vaccination. CBER is now planning to take "swift action" following this new safety concern. The labels for the Covid vaccines already warn against the risk of myocarditis and pericarditis.
The companies, though, say the risk of myocarditis is much higher following a Covid infection than a vaccine. In a September release, Pfizer said the risk of myocarditis after Covid is 42 times higher than the risk after receiving a Covid shot. The company cited a systematic review and meta analysis.
The National Institutes of Health, in an October 2022 report, said contracting Covid increases the risk of myocarditis by 16-fold. In the same study, fewer than one person per 100,000 experienced myocarditis following Covid vaccination.
Leerink's Foroohar says the memo takes an "inflammatory tone," describing "coercive and unethical Covid-19 vaccine mandates in young people."
"We do not know how many fewer kids would have died had they been vaccinated, and we do not know how many more kids died from taking vaccines than has been voluntarily reported," Prasad, CBER's director, said in the memo.
Foroohar calls the memo another negative development for mRNA vaccine makers that could add to vaccine skepticism and continued U.S. vaccination declines.
CBER is now planning to make several changes to the vaccine regulatory pathway.
This includes premarket randomized trials assessing clinical goals beyond immunogenicity, or how effective vaccines are at stimulating the immune system. CBER will also no longer allow companies to use immunogenicity studies to expand the addressable population for already approved vaccines.
Moderna stock, which has climbed 16% from Nov. 20-28, saw shares hit their 50-day moving average on Friday and then tumble well below that mark on Monday.
Similarly, BioNTech shares hit a 50-day ceiling on Friday and skidded Monday. Dynavax shares are well above their 50-day and 200-day lines despite Monday's drop.
The memo also highlights Prasad's plan to require additional effectiveness data from pneumococcal vaccine studies. These vaccines prevent diseases like pneumonia, meningitis and other infections. Vaxcyte (PCVX) stock took that news on the nose, falling 8.2% to 45.52.
In an email to Leerink Partners analyst David Risinger, the company noted Prasad's memo states firms must show their pneumonia vaccines reduce pneumonia and not just generate antibodies capable of tackling the virus.
"As written, this aligns with how post-marketing evidence has historically been regenerated in the pneumococcal vaccine class, where licensure has been based on established immunologic correlates of protection, with additional real-world data collected after approval," Vaxcyte said, according to Risinger. "Our approach is aligned with other PCV developers."
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