COVID vaccines heart risk warning update issued by FDA

The Food and Drug Administration (FDA) has expanded its warnings on Pfizer and Moderna COVID-19 vaccines about the risks of two heart conditions.

These manufacturers, the two main COVID-19 vaccine providers, will now have to update their information about the chances of myocarditis and pericarditis, the FDA said in a safety communication notice issued Wednesday.

Newsweek has contacted Pfizer and Moderna, via email, for comment.

Why It Matters

Myocarditis, when the heart muscle gets inflamed, can make it harder for the heart to pump blood possibly causing chest pain, shortness of breath and irregular heartbeats. Pericarditis, when the thin lining around the heart (called the pericardium) becomes inflamed, can also cause sharp chest pain that feels worse when lying down.

Pfizer and Moderna have both advised doctors about cases of myocarditis and pericarditis in young men who have taken the vaccine since 2021 but the FDA has asked them to expand these warnings.

It comes with an ongoing conversation about vaccines with Health Secretary Robert F. Kennedy Jr. appointing new vaccine advisers to debate the continuing use of COVID-19 vaccines for certain groups, including pregnant women.

Critics worry that Kennedy Jr. is undermining trust in vaccines, while he and his supporters argue that more transparency about the risks of vaccines is needed.

What To Know

The new warning says that the risk of myocarditis and pericarditis has shown to be highest among men between the ages of 12 and 24. Previous labels said the issue was a risk for men aged 12 to17, according to The Associated Press.

It also says that there were around 8 cases per 1 million people who got the 2023-2024 COVID shots between the ages of 6 months and 64 years old, citing analyses of commercial health insurance claims data.

This label change seemingly conflicts with a previous conclusion published by the Centers for Disease Control and Prevention (CDC) which concluded that there was no increased risk of myocarditis detected in government vaccine injury databases for COVID-19 shots dating back to 2022.

Infectious diseases expert Amesh Adalja, an assistant professor at the Johns Hopkins University Center for Health Security, was one of several who spoke out against the new warning.

“Myocarditis and pericarditis were delimited side effects identified early on with mRNA COVID-19 vaccines,” he told Newsweek. “These small risks, which are well known, have largely diminished as they were really concentrated with the initial two-dose series given to adolescent/young adult males.”

“To push the label change now—in the current anti-vaccine context of RFK’s HHS—can only be interpreted as a way to dissuade people away from the vaccines,” he added.

Robert Morris, a public health specialist at the University of Washington, also spoke out against the new warning, arguing that, while the risk of these heart conditions needs to be considered, a more specific approach should be taken.

“We should be investigating who is prone to myocarditis to see if we can predict and mitigate that risk,” he told The Associated Press.

Earlier this month, Kennedy Jr. dismissed all 17 members of the Advisory Committee on Immunization Practices (ACIP), a key panel that guides national vaccine policy.

“The committee has been plagued with persistent conflicts of interest and has become little more than a rubber stamp for any vaccine,” he wrote in an op-ed for The Washington Post. “It has never recommended against a vaccine—even those later withdrawn for safety reasons.”

Republican Senator Bill Cassidy of Louisiana, a physician who had voiced concerns about Kennedy’s nomination but ultimately supported his confirmation as health secretary, was one of several who expressed worries about the move.

He wrote on X that he spoke with Kennedy shortly after the announcement and said: “The concern now is that ACIP could be stacked with individuals whose only familiarity with vaccines is rooted in skepticism.”

What People Are Saying

The new warning has to include the following language: “Based on analyses of commercial health insurance claims data from inpatient and outpatient settings, the estimated unadjusted incidence of myocarditis and/or pericarditis during the period 1 through 7 days following administration of the 2023-2024 Formula of mRNA COVID-19 vaccines was approximately 8 cases per million doses in individuals 6 months through 64 years of age and approximately 27 cases per million doses in males 12 through 24 years of age.

“Follow-up information on cardiovascular outcomes in hospitalized patients who had been diagnosed with COVID-19 vaccine-associated myocarditis is available from a longitudinal retrospective observational study. Most of these patients had received a two-dose primary series of an mRNA COVID-19 vaccine prior to their diagnosis. In this study, at a median follow-up of approximately 5 months postvaccination, persistence of abnormal cardiac magnetic resonance imaging (CMR) findings that are a marker for myocardial injury was common. The clinical and prognostic significance of these CMR findings is not known.”

Dr. Robert Morris said about the new warning: “They are right to suggest that we need to consider myocarditis risks associated with the vaccine, but what they propose is exactly the wrong solution.”

Amesh Adalja said: “This seems to be something not driven from a desire to understand the now even more rare phenomenon and make it even more rare but something else.”

What Happens Next

The FDA has required Pfizer and Moderna to “conduct a study to assess if there are long-term heart effects in people who have had myocarditis after receiving an mRNA COVID-19 vaccine which are currently taking place.

“Continuous monitoring and assessment of the safety of all vaccines, including the mRNA COVID-19 vaccines, is an FDA priority and we remain committed to informing the public when we learn new information about these vaccines,” the FDA said.