The US Food and Drug Administration intends to put a “black box” warning on Covid-19 vaccines, according to two people familiar with the agency’s plans, reports BritPanorama.
A *boxed warning*, which appears at the top of prescribing information for medicines, is the agency’s most serious, designed to warn about risks such as death or life-threatening or disabling reactions that should be weighed against the benefits of the intervention. These warnings can also be used when a risk might be lowered by using a medicine in a targeted way, such as only in certain groups.
Boxed warnings on opioids, for example, warn about risks of abuse, addiction, overdose and death. The acne medication Accutane carried a warning about the risks of birth defects when used during pregnancy. ACAM2000, a smallpox and mpox vaccine, has a warning about complications such as heart inflammation and encephalitis.
The plan to install the warnings for Covid-19 vaccines is being orchestrated by Dr. Vinay Prasad, the FDA’s chief medical and scientific officer and director of the agency’s Center for Biologics Evaluation and Research, according to one person, who declined to be named due to lack of authorization to disclose this information.
This plan has not been finalized and may still change. It remains unclear whether the plans for the warnings, expected to be unveiled by the end of the year, would be applied only to mRNA vaccines or to all Covid-19 vaccines, or whether they would apply to all age groups. Currently, three vaccines are approved by the FDA for use in the US, with two of them — from Pfizer and Moderna – utilizing mRNA technology, which has been a central focus of the administration.
“Unless the FDA announces it, any claim about what it will do is pure speculation,” said US Department of Health and Human Services spokesperson Andrew Nixon.
In response to inquiries about the FDA’s plans, Moderna pointed to a statement it issued in September regarding the safety of its Covid-19 vaccine, SpikeVax. The company noted that its vaccine’s safety is “rigorously monitored by Moderna, the US FDA, and regulators in more than 90 countries,” asserting that, with over one billion doses distributed worldwide, these systems “have not reported any new or undisclosed safety concerns in children or pregnant women.”
Pfizer also issued a statement in September asserting the safety and efficacy of its Covid-19 vaccine. These statements came in the wake of reports that federal health officials might seek to connect vaccines to safety risks in pregnant women and children. Pfizer did not provide additional comments at that time.
One study estimated that in their first year of use, Covid-19 vaccinations averted nearly 20 million deaths globally. Children vaccinated during the 2024-25 respiratory virus season had a “substantially lower risk” of emergency department and urgent care visits related to the virus, according to a CDC report published Thursday. The vaccines were approximately 76% effective in preventing these outcomes among healthy children aged 9 months to 4 years, and around 56% effective among those aged 5 to 17 compared to unvaccinated children.
The rapid development of Covid-19 vaccines during the pandemic, under the project dubbed Operation Warp Speed, was one of the notable achievements of President Donald Trump’s administration. Some Republican lawmakers have suggested this initiative deserves recognition such as a Nobel Peace Prize. However, Trump appointed Robert F. Kennedy Jr. — a known vaccine skeptic — as Health and Human Services Secretary, leading to controversy given his criticisms of public health expertise.
Administration targets vaccines
Kennedy and his allies have consistently questioned the safety and effectiveness of the Covid-19 vaccines, which were evaluated in placebo-controlled trials involving about 75,000 participants and distributed to millions globally during the pandemic.
Prasad has been a controversial figure, both in his role at the FDA and previously as a podcaster and professor in the Department of Epidemiology and Biostatistics at the University of California at San Francisco. A critic of the government’s response to the pandemic and vaccine policy, he was appointed CBER director under FDA Commissioner Dr. Marty Makary in May, but resigned in July amid pressure from the White House and activist Laura Loomer, only to return to the agency weeks later.
In late November, Prasad sent a memo to staff within CBER claiming that staff in the FDA’s Office of Biostatistics and Pharmacovigilance had “found that at least 10 children have died after and because of receiving Covid-19 vaccination.” He did not provide additional information but promised “swift action” in response.
“The FDA takes very seriously any death that is attributed to a regulated medical product,” Nixon stated.
Prasad has highlighted myocarditis, a very rare side effect following administration of mRNA vaccines, which was observed soon after these shots were initially recommended. This side effect predominantly affected boys and young men.
A presentation from the US Centers for Disease Control and Prevention in June indicated that most adolescents and young adults recovered from myocarditis after vaccination, and found no known deaths or heart transplants related to this condition. Rates of myocarditis have decreased significantly in recent years as the recommended spacing between the mRNA vaccine doses has been extended.
In May, the FDA mandated safety warnings be included in the prescribing information for Pfizer and Moderna’s Covid-19 vaccines regarding the risk of myocarditis and pericarditis, with the labels now stating, “the observed risk has been highest in males aged 12 to 24 years.”
On Tuesday, Children’s Health Defense, the nonprofit led by Kennedy before his presidential campaign, filed a citizen petition demanding the agency revoke the licenses for the vaccines, arguing that the mRNA vaccines are misbranded because they were initially approved under emergency use authorization standards.
HHS also announced this week that the FDA was investigating whether deaths “across multiple age groups” might be related to Covid-19 vaccines.
Prasad’s memo, which suggested a significant overhaul of FDA vaccine regulation, alarmed public health experts, many of whom called for the supporting data to be disclosed. A group of a dozen former FDA commissioners expressed their concerns in an open letter, highlighting the potential implications of sweeping new assertions about vaccine safety by the FDA.
‘Death by a thousand cuts’
“What’s happening now is death by a thousand cuts,” remarked one source familiar with the agency’s operations, who chose to remain anonymous as they were not authorized to share this information.
Recent messaging from the administration that contradicts established scientific evidence — such as claims that vaccines carry greater risks when administered concurrently — is reportedly undermining public confidence in these vital medical interventions.
“What we’re witnessing is misinformation and aggregate lies that will discourage the population from vaccinating. This could lead to unnecessary loss of life, and it’s very concerning,” the source added.
Dr. Aaron Kesselheim, who leads the Program on Regulation, Therapeutics and Law at Harvard University, noted that such warnings can be initiated by either the manufacturer or the FDA. Typically, the agency notifies the public when investigating safety questions around a drug or vaccine, and may consult an independent advisory committee to provide expert advice on the safety data.
However, none of these procedures appear to have been followed regarding the current warnings. The FDA’s media office did not respond to questions about whether there was a plan to convene an advisory committee meeting on the matter.
Dr. Kesselheim expressed concern that the lack of a transparent process indicates a departure from established protocols. “My concern is that in this case, there’s not a process,” he said. “There isn’t the same opportunity for discussion and good-faith examination of the data that drives this decision.”
He added, “My concern is that this will be perceived as another instance where the FDA is making decisions based on political objectives rather than thorough public scrutiny of scientific evidence.”
Others support the need for greater transparency regarding whether deaths can be directly linked to the vaccines. “The FDA has not released any data on how they determined that the Covid vaccines were linked to these pediatric deaths,” said Dr. Fiona Havers, a medical epidemiologist who resigned from the CDC over perceived administrative interference in vaccine programs.
“Very rare adverse events with vaccines can occur. I don’t know if they did in this case, because, again, they haven’t released any information,” she argued. “But to focus only on potential vaccine harms without acknowledging the thousands of hospitalizations and many pediatric deaths these vaccines have prevented is not responsible and should not characterize how our government communicates vaccine information to the public.”
Dr. Angela Rasmussen, a virologist at the University of Saskatchewan and co-editor-in-chief of the journal *Vaccine*, questioned the rational basis for a black-box warning. “Scientifically, I don’t think it makes any sense at all, because we haven’t seen any of this data,” she stated. “It presumably will imply that ‘this vaccine is dangerous.’ The FDA reserves black box warnings for products associated with serious safety risks, making any potential warning nonsensical unless firmly based on credible evidence.”
Rasmussen further expressed her concerns regarding Prasad’s long-standing and documented opposition to the Covid-19
