The Centers for Disease Control and Prevention (CDC) is investigating reports that some teenagers and young adults vaccinated against COVID may have experienced heart problems, according to the agency’s advisory group.
The CDC’s Advisory Committee on Immunization Practices in a May 17 statement said, reports of myocarditis to date seemed to occur predominantly in adolescents and young adults, more often in males than females, more often following the second dose and typically within four days after vaccination. Most cases appeared to be “mild” and follow-up is ongoing.
Myocarditis is inflammation of the heart muscle that can lead to cardiac arrhythmia and death. According to researchers at the National Organization for Rare Disorders, myocarditis can result from infections, but “more commonly the myocarditis is a result of the body’s immune reaction to the initial heart damage.”
The CDC’s Vaccine Safety Technical (VaST) Work Group has reviewed post-authorization COVID vaccine safety data on a weekly basis since the first COVID vaccine was rolled out in the U.S. in December 2020. At the time, vaccine recipients had to be 18 years old or older.
On May 13, the CDC signed off on expanded use of Pfizer’s COVID vaccine for ages 12- to 15-year-olds. The Pfizer vaccine so far is the only COVID vaccine to have received EUA for young teens.
The VaST session on May 17 included several presentations on myocarditis following mRNA vaccines Pfizer and Moderna.The data came from the U.S. Department of Defense, the Vaccine Adverse Event Reporting System (VAERS) and Vaccine Safety Datalink.
There were also brief updates from the Veteran’s Administration and the CDC’s Clinical Immunization Safety Assessment Project groups about plans for future investigation of myocarditis.
The CDC said its monitoring systems had not found more cases of myocarditis than would be expected in the population, but members of the committee on vaccinations said healthcare providers should be made aware of the reports of the “potential adverse event.”
“We look forward to seeing more data about these cases, so we can better understand if they are related to the vaccine or if they are coincidental,” said Dr. Yvonne Maldonado, chair of the American Academy of Pediatrics’s Committee on Infectious Diseases.
“Meanwhile, it’s important for pediatricians and other clinicians to report any health concerns that arise after vaccination,” Maldonado said.
The preliminary report by a committee tasked with monitoring vaccine side effects found 62 cases of myocarditis, including two deaths, in people who received the Pfizer vaccine. Fifty-six of the cases occurred after the second dose of the vaccine, and 55 cases occurred in men — most between the ages of 18 and 30.
Israel’s pandemic response coordinator, Nachman Ash, confirmed “tens of incidents” of myocarditis occurred in vaccinated people, primarily after the second dose, but emphasized the health ministry had yet to draw any conclusions.
Israeli researchers presented their findings to the Israeli Health Ministry Director-General, Pfizer, the CDC and the U.S. Food and Drug Administration.
EU regulators in May called on Pfizer and Moderna to provide additional data related to the companies’ COVID vaccines and a potential link to heart inflammation, after the agency completed a safety review of all four COVID vaccines authorized for emergency use in the EU.
A search in VAERS revealed 288 cases of pericarditis and myocarditis reported in the U.S following COVID vaccination between Dec.14, 2020 and May 14. Of the 288 cases reported, 158 cases were attributed to Pfizer, 110 cases to Moderna and 19 cases to Johnson & Johnson’s COVID vaccine.