US FDA Adds Warning About Possible Risk Of Heart Inflammation To Pfizer, Moderna mRNA Covid-19 vaccines

The U.S drug regulator Food and Drug Administration (FDA) on Friday (June 25) added a warning to the literature that accompanies Pfizer Inc-BioNTech and Moderna Covid-19 vaccine shots to indicate the rare risk of heart inflammation after its use.

FDA announced revisions to the patient and provider fact sheets for the Moderna and Pfizer-BioNTech COVID-19 vaccines to indicate increased risks of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the tissue surrounding the heart) following vaccination.

For each vaccine, the fact sheets for healthcare providers have been revised to include a warning that reports of adverse events suggest increased risks of myocarditis and pericarditis, particularly after the second dose and with onset of symptoms within a few days after vaccination, the FDA said.

FDA update comes after following an extensive review of information and the discussion by CDC’s Advisory Committee on Immunization Practices meeting on Wednesday.

A panel comprising of expert advisors to the Centers for Disease Control and Prevention (CDC) on Wednesday (Jun 23) acknowledged that there was a “likely association” between mRNA Covid-19 vaccines and an elevated risk of heart issues in adolescents and young adults.

"Clinical presentation of myocarditis cases following vaccination has been distinct, occurring most often within 1 week after dose two, with chest pain as the most common presentation, " said Grace Lee, MD, chair of safety subcommittee of Advisory Committee on Immunization Practices (ACIP) that advices CDC.

"mRNA vaccines may be a new trigger for myocarditis, yet it does have some different characteristics," said Matthew Oster, MD, MPH, from the CDC's COVID-19 Vaccine Task Force.

The most common symptoms reported by patients were chest pain, shortness of breath, and difficulty sleeping.

Based on evidence, the cases were mostly concentrated on younger groups, particularly men under 30, having higher rates of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) following vaccination with the shots from Moderna or Pfizer-BioNTech. Most cases have occurred soon after the second shot of the two-dose regimens.

Immunization Safety Office at the CDC, said the agency has so far received reports of 1,226 cases of myocarditis, with 827 (67.5%) reported after dose two of either the Moderna or Pfizer vaccine.

Of those cases identified after second doses, 563 followed the Pfizer vaccine series. In total, that's approximately 12.6 heart inflammation cases per million doses administered in the United States.

Among the 1,226 patients, 484 are younger than 29, and roughly two-thirds are men.

The myocarditis and pericarditis associated with vaccines are usually mild and respond well to a course of treatment with non-steroidal anti-inflammatories.

Officials said they are planning to add warnings about myocarditis and details about symptoms to Covid-19 vaccine fact sheets provided to administrators of the shots and people who get them