Post-Vaccination Heart Inflammation Highest Among Young Men, Likely Underreported: CDC Study

By Zachary Stieber
Zachary Stieber
Zachary Stieber
Reporter
Zachary Stieber covers U.S. and world news. He is based in Maryland.
January 27, 2022 Updated: January 27, 2022

Heart inflammation following COVID-19 vaccination was higher than expected in multiple age groups and was particularly pronounced in young men, according to a new data analysis from Centers for Disease Control and Prevention (CDC) researchers.

Analyzing records submitted to the Vaccine Adverse Event Reporting System (VAERS) between December 2020 and August 2021, the researchers found that young males aged 12 to 17 were the most likely to suffer post-vaccination myocarditis, a form of heart inflammation that can lead to death.

The rates were the highest after the second dose and after vaccination with the Pfizer-BioNTech jab. Males aged 12 to 15 experienced 70.7 myocarditis cases per million doses administered and males aged 16 or 17 experienced 105.8 cases per million doses, according to the peer-reviewed study, published in the Journal of the American Medical Association.

Some experts have called for U.S. health officials to recommend certain youth get the second shot of the primary regimen months after the first because of the elevated risk of heart inflammation but officials have thus far refused to adjust the scheduling recommendation, which is around three weeks for Pfizer’s shot and a month for Moderna’s jab.

Both vaccines are built on messenger RNA technology.

The rate after Moderna vaccination was lower for the 12- to 17-year-old males but higher in young men aged 18 to 24. The rates were 56.3 cases per million doses after the Moderna second shot 52.4 cases per million doses after the second Pfizer shot.

CDC researchers say most post-vaccination myocarditis cases eventually resolve but that they’re investigating reports of two deaths among people younger than 30 which may be linked to the vaccines. The reports have been under investigation since at least November, according to a presentation (pdf) delivered to the agency’s vaccine advisory panel that month.

“Even though almost all individuals with cases of myocarditis were hospitalized and clinically monitored, they typically experienced symptomatic recovery after receiving only pain management. In contrast, typical viral cases of myocarditis can have a more variable clinical course. For example, up to 6% of typical viral myocarditis cases in adolescents require a heart transplant or result in mortality,” they wrote.

Myocarditis was not identified as an issue in clinical trials but has since emerged as one of the most severe side effects following Pfizer or Moderna vaccination, with higher-than-expected rates among young men and some young women.

The CDC is working on studying the long-term impact of post-vaccination myocarditis.

The condition often prevents youth from participating in competitive sports for at least three months and cardiac MRIs showed abnormal results for about a quarter of a subset of cases three months after presentation, Dr. Matthew Oster, a CDC researcher, told the advisory panel on Nov. 2, 2021.

Oster, who worked on the newly published study, told The Epoch Times in an email that post-vaccination myocarditis “appears to be high” but that it’s “still an extremely rare condition.”

CDC
A general view of the Centers for Disease Control and Prevention (CDC) headquarters in Atlanta on Sept. 30, 2014. (Tami Chappell/Reuters)

Oster and a CDC spokesperson alleged that the risk of myocarditis is higher for all age groups from COVID-19 than from the vaccines, but the agency passed on studies and presentations that date no later than the Nov. 2 meeting. The CDC’s webpage on myocarditis and pericarditis, another form of heart inflammation, following COVID-19 vaccination has not been updated since Nov. 12.

Since then, outside researchers have found that the risk of heart inflammation was higher from Moderna’s vaccine than COVID-19 for people younger than 40 and that young men are more likely to get myocarditis after receiving the second shot of Pfizer or Moderna’s vaccine, or the Pfizer booster, than from COVID-19.

VAERS is a passive reporting system that is maintained by the CDC and the Food and Drug Administration, which encourage health care workers to report post-vaccination adverse events. Patients and loved ones can also submit reports.

Researchers identified 1,991 reports of myocarditis submitted to VAERS in the timeframe studied, during which over 354 million doses of Pfizer or Moderna shots were administered. Only 1,626 reports met the case definition of myocarditis, and those were analyzed for the study.

VAERS data is often subject to underreporting and the CDC researchers said underreporting of myocarditis incidents following vaccination is likely.

“Therefore, the actual rates of myocarditis per million doses of vaccine are likely higher than estimated,” they said.

Pfizer and Moderna didn’t respond to requests for comment.

In another study published this week, as a correspondence to The New England Journal of Medicine, researchers said they analyzed a surveillance system managed by the Israeli Ministry of Health and found 18 cases of myocarditis leading to hospitalization following Pfizer vaccination of approximately 731,000 12- to 15-year-olds, some of whom received a second dose.

Two cases were excluded because of “reasonable alternative diagnoses,” one was said to have actually occurred in an unvaccinated individual, and two were deemed “unlikely to be related to the vaccine.” The 13 other patients were all discharged from the hospital after a mean duration of 3.1 days.

Researchers pegged the risk of myocarditis among males as 8 cases per 100,000 after the second dose and 0.6 cases per 100,000 among females after the second dose.

“In conclusion, the incidence of myocarditis leading to hospitalization among adolescents who received the second dose of the BNT162b2 vaccine was low but was higher than among recipients of the first vaccine dose and proportionately numerically higher than in recent estimates of incidence among unvaccinated persons,” the scientists said.

Zachary Stieber
Zachary Stieber covers U.S. and world news. He is based in Maryland.