Heart Inflammation 7 Times More Likely With Covid Than Vaccines

Frontiers journal logo

Covid vaccines have been a controversial topic, to say the least. Now, a new study from Frontiers in Cardiovascular Medicine helps answer one of the questions about vaccine safety. According to scientists at Penn State College of Medicine, the risk of developing myocarditis (inflammation of the heart muscle) is seven times higher with a Covid-19 infection than with a coronavirus vaccine.

Symptoms of myocarditis include chest pains, shortness of breath, and/or an irregular heartbeat. The inflammation can lead to heart failure and death in severe cases.

“Our findings show that the risk of myocarditis from being infected by Covid-19 is far greater than from getting the vaccine,” said Dr. Navya Voleti, a resident physician in the Department of Medicine at Penn State Health Milton S. Hershey Medical Center. “Moving forward, it will be important to monitor the potential long-term effects in those who develop myocarditis.”

Myocarditis is a known complication of SARS-CoV-2 infection. Although vaccines have been shown to reduce severe Covid symptoms, the mRNA ones have been linked with heart complications — particularly myocarditis in teenage boys. However, the relative risk of myocarditis resulting from vaccines versus infections had not been well characterized in large studies.

Study Details

Penn State researchers conducted the largest study to date on the risk of developing myocarditis as a result of having the coronavirus vs. experiencing inflammation following a Covid vaccination. The researchers compared patients with Covid — vaccinated and unvaccinated — to those without the virus. They found the risk of myocarditis was 15 times higher in Covid patients, regardless of vaccination status, compared to those who did not contract the virus.

Scientists also separately compared the cases of myocarditis in those who received the vaccines to those in unvaccinated subjects. According to the findings, the rates of myocarditis in those who were vaccinated were only twofold higher than in unvaccinated people.

The researchers concluded that the risk of myocarditis due to COVID-19 was seven times higher than the risk related to the vaccines.

22 Studies & Millions of Patients

Investigators conducted a systematic review and meta-analysis of 22 studies published worldwide from December 2019–May 2022. The studies included nearly 58 million patients who reported cardiac complications and belonged to one of two groups: the 55.5 million who were vaccinated against Covid compared to those who were not vaccinated (vaccination group), and the 2.5 million who contracted the virus compared to those who did not contract the virus (COVID-19 group).

In the vaccination group: The researchers separately compared the risk of myocarditis for various Covid vaccines, including mRNA (Pfizer, Moderna), Novavax, AstraZeneca, and Johnson and Johnson. The median age of the study population was 49 years, and 49% were men. The median follow-up time after infection or COVID-19 vaccination was 28 days.

The researchers found that among those diagnosed with myocarditis after receiving the vaccine or having Covid, the majority (61%) were men. Of patients diagnosed with myocarditis in both vaccination and Covid groups, 1.07% were hospitalized and 0.015% died.

“COVID-19 infection and the related vaccines both pose a risk for myocarditis. However, the relative risk of heart inflammation induced by COVID-19 infection is substantially greater than the risk posed by the vaccines,” said Dr. Paddy Ssentongo, a resident physician in the Department of Medicine at Penn State Health Milton S. Hershey Medical Center and the lead author of the study. “We hope our findings will help mitigate vaccine hesitancy and increase vaccine uptake.”

Conclusion

From the authors: In this systematic review and meta-analysis, we found that the risk of incident myocarditis is more than seven times higher in persons who were infected with the SARS-CoV-2 than in those who received the COVID-19 vaccines. These findings support the continued use of mRNA COVID-19 vaccines among all eligible persons per the CDC and WHO recommendations.

READ FULL STUDY