by James Lyons-Weiler, PhD, Popular Rationalism, ©2026
(Feb. 10, 2026) — In June 2025, the U.S. Food and Drug Administration instituted what is formally known as a class Safety Labeling Change to the prescribing information of mRNA COVID‑19 vaccines, requiring updated warnings about the risks of myocarditis and pericarditis following administration of these products. In conjunction with manufacturers, the FDA directed that safety labeling for the Pfizer‑BioNTech and Moderna mRNA vaccines be revised to convey new safety information about the estimated risk of heart‑related inflammatory conditions observed following vaccination, including unadjusted incidence estimates and clinical findings from post‑approval studies. This expanded warning explicitly noted that the highest estimated incidence occurred in younger males, particularly in the 12‑ to 24‑year age range, based on data collected in mid‑2025 during insurance claims analyses and safety monitoring data. This regulatory action marked a significant evolution in how the agency communicates and manages emerging safety signals associated with widely used vaccines.
This labeling change was not an isolated press release buried in a technical docket. Leaders within the agency, including Vinay Prasad, MD, MPH and Martin A. Makary, MD, MPH, published a peer‑reviewed Viewpoint in Journal of the American Medical Association (JAMA; July 2025) outlining the rationale and significance of the FDA’s safety labeling update. They explained that the “class Safety Labeling Change” was intentionally pursued and communicated through scientific literature in addition to regulatory outlets to underscore its scientific basis.
In early 2026, Prasad and Makary responded to a letter to the editor defending this shift by articulating regulatory epistemology: the FDA’s obligation to grant marketing authorization for medical products only when there is substantial certainty that the benefits outweigh the risks, and to admit when evidence is insufficient to support generalized use of additional vaccine doses in certain populations.
In their reply, they posed the rhetorical question of whether a healthy seven‑year‑old child would receive meaningful benefit from repeated mRNA boosters if she has already experienced multiple SARS‑CoV‑2 infections and pointedly acknowledged that physicians do not know with certainty the benefits in such scenarios. They invoked the FDA’s own regulatory framework, the limits of available evidence, and the practice of stratifying authorization by age and risk categories.
The essence of their argument was that scientific regulators must explicitly weigh benefits against risks and refuse authorization when benefit is uncertain or unmeasured. This is not a rhetorical flourish. The legal and scientific standards governing FDA decisions require that benefits outweigh risks with substantial certainty before a product is authorized or its indications are expanded. When evidence is incomplete, wishing for benefit, averaging outcomes across heterogeneous populations, or deferring to external pressure cannot substitute for demonstrable, compelling data on net benefit. What Prasad and Makary encoded in that letter is not simply agency talking points but an articulation of prior probability thresholds that, in principle, govern rational decision‑making under uncertainty.
As of late 2025, the U.S. Centers for Disease Control and Prevention continues to state that cases of myocarditis and pericarditis have been rarely observed following receipt of COVID-19 vaccines used in the United States. In the agency’s Clinical Considerations for COVID-19 Vaccination, CDC notes that when these inflammatory cardiac events do occur after vaccination, they have been reported most frequently in adolescent and young adult males within about 7 days after receipt of a second dose of an mRNA COVID-19 vaccine, while also acknowledging that cases have occurred in females, other age groups, and in association with other doses.
CDC’s guidance further explains that most patients with myocarditis after mRNA COVID-19 vaccination have experienced resolution of symptoms by the time of hospital discharge, and it continues to counsel that clinicians should consider myocarditis or pericarditis in persons presenting with acute chest pain, shortness of breath, or palpitations after vaccination, noting that in younger children symptoms may be less specific. On its Safety Considerations for COVID-19 Vaccines page, CDC explicitly advises that counseling should include awareness of these symptoms and the need to seek care if they develop, particularly during the week following vaccination. CDC’s clinical recommendations still direct healthcare providers to report suspected cases to vaccine safety monitoring systems such as VAERS.
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