The FDA Just Released a New Warning About This COVID Vaccine Side Effect

The agency has revealed important new data about one coronavirus shot.

It's been more than a year since the first COVID vaccines were made available to all adults in the U.S. Since then, both the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) have been working to get shots into the arms of all Americans. According to the latest data from the CDC, 77.9 percent of the total U.S. population has received at least one dose of a COVID vaccine, but just 66.7 percent has been fully vaccinated so far. And the rate of vaccine doses being administered is falling, with a 9.5 percent decrease from the week prior.

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There are currently still only three vaccines authorized for use in the U.S.: Moderna, Pfizer, and Johnson & Johnson. But as time has passed throughout the last year, officials have started recommending both Moderna and Pfizer over the one-shot Johnson & Johnson vaccine because the two mRNA vaccines have shown that they can produce stronger and more durable protection, especially in the face of new, more transmissible variants. Now, some Americans are already on their third or fourth shot of Moderna or Pfizer.

Meanwhile, the FDA is gearing up to discuss the possibility of introducing a fourth vaccine into the mix. According to The Washington Post, advisers to the agency are scheduled to discuss whether or not a COVID vaccine produced by Novavax, a Maryland-based biotech company, should be authorized on June 7. The Novavax vaccine is a two-shot formula like the mRNA vaccines, but unlike Moderna and Pfizer, this vaccine uses more traditional technology that has been used for many vaccines in the past, per NPR.

"We all know that there are certain people in the population who are still concerned about a vaccine that is relatively new in the arena of vaccinology," top White House COVID adviser Anthony Fauci, MD, told NPR. "And they may want a more classical vaccine that we have years and years of experience with."

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A Novavax trial of nearly 30,000 volunteers aged 18 and older, conducted between Dec. 2020 and Sept. 2021, also found that the vaccine was about 90 percent effective at preventing mild, moderate, and severe COVID. While this might seem like a clear win for the country's push to get the unvaccinated inoculated, the FDA is also warning of a concern with this shot.

The agency recently revealed that recipients of the Norovax COVID vaccine might have a very small risk of heart inflammation, CNN reported. According to the news outlet, there were six cases of myocarditis and pericarditis among patients in the trial, detected within 20 days of them taking the protein-based shot. Myocarditis is inflammation of the heart muscle, while pericarditis is inflammation of the lining outside the heart, per the CDC.

"These events raise the concern for a causal association with this vaccine, similar to the association documented with mRNA COVID-19 vaccines," FDA staff wrote in briefing documents released June 3. According to the agency, five of the post-vaccination heart inflammation cases were among males between 16 to 67 years old. And of the six cases, five were hospitalized but have since recovered.

Novavax addressed the FDA's concerns over heart inflammation in a statement on June 3, denying that there is sufficient evidence to "establish a causal relationship" between its vaccine and this health issue. According to the company, the rate of myocarditis in vaccinated participants was similar to that of those in the placebo group.

"Throughout the pandemic, as publicly available vaccines have been administered, there have been numerous investigations into findings related to myocarditis. We have learned that we can expect to see natural background events of myocarditis in any sufficiently large database, and that young males are at higher risk. Myocarditis is most often caused by nonspecific viral infections," Novavax said. "We believe there is insufficient evidence to establish a causal relationship. We will continue to monitor all adverse events, including myocarditis and pericarditis."

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