The Food and Drug Administration (FDA) is currently investigating potential links between COVID-19 vaccines and adult deaths as part of a comprehensive safety review. This inquiry expands upon a previous focus on adverse effects in children, signaling a broader examination of vaccine safety across multiple age groups. The investigation comes during a time of significant change in vaccine guidance by U.S. Health and Human Services Secretary Robert F. Kennedy Jr., who has raised concerns about vaccine safety.
An FDA spokesperson stated, “The FDA is doing a thorough investigation, across multiple age groups, of deaths potentially related to COVID vaccines,” as reported to Bloomberg on Tuesday. Despite numerous studies affirming the safety of COVID-19 vaccines, Kennedy has consistently questioned their efficacy and safety, recently canceling substantial funding for mRNA vaccine initiatives, which are critical to the vaccines produced by Moderna Inc. and Pfizer Inc..
Stock market responses to these developments reflected investor apprehension. Shares of Moderna fluctuated, briefly turning negative before closing with a 1% gain, while Pfizer’s shares fell by 1.7%. Both companies have faced declining revenues as pandemic-related demand wanes and many individuals choose to forgo annual vaccinations. Nevertheless, COVID-19 vaccines still generated billions of dollars in revenue for both companies in 2024.
In response to inquiries regarding vaccine safety, a spokesperson for Moderna emphasized that the safety of its vaccine is rigorously monitored by both the company and regulatory agencies in over 90 countries. Similarly, a Pfizer representative highlighted that more than 5 billion doses of its vaccine have been distributed worldwide, making it one of the most extensively monitored medical products globally.
Concerns about new regulatory approaches have emerged. Vinay Prasad, the FDA’s senior vaccine regulator, reportedly indicated in a leaked internal memo that the agency would adopt stricter standards for vaccine approvals. He claimed that a review revealed ten child fatalities associated with COVID-19 vaccinations, although he provided no evidence to substantiate this assertion. This claim has prompted a backlash from a dozen former FDA leaders, who criticized the shift in vaccine regulation in a recently published article in a prominent medical journal.
The implications of these developments could be significant. Michael Kinch, a drug development expert and chief innovation officer at Stony Brook University, cautioned that expanding the investigation might lead to increased public skepticism about vaccine safety. He remarked, “The actions by an irresponsible few could have long-lasting implications for the health of the many.”
Despite ongoing concerns, research indicates that COVID-19 vaccinations have played a crucial role in reducing mortality rates. A study published in July by researchers at Stanford University and Italian institutions estimated that COVID-19 vaccines prevented 2.5 million deaths globally between 2020 and 2024, with the majority of the benefits accruing to older adults.
Reports in medical literature have noted instances of deaths potentially linked to myocarditis, an inflammation of the heart muscle, following COVID-19 vaccinations. One case was documented in the New England Journal of Medicine. Another study in the same journal found that among 5.1 million Israelis who received the Pfizer vaccine, myocarditis cases were typically mild, although there were some severe cases and one death.
As of March 2022, approximately 53% of the adult U.S. population had received a complete COVID-19 vaccination series along with at least one booster shot, according to data from the Centers for Disease Control and Prevention (CDC). However, recent CDC statistics reveal that only 23% of American adults received COVID-19 vaccines or boosters during the respiratory illness season from fall 2024 to spring 2025.
In addition to its investigation into COVID-19 vaccines, the FDA is also reviewing safety data related to RSV vaccines for infants, as stated by the Department of Health and Human Services on Tuesday. The ongoing inquiries reflect a complex landscape of vaccine safety and public health as authorities navigate the challenges posed by evolving vaccination strategies and public sentiment.
