Risk of Myocarditis 7 Times Greater with COVID-19 Infection vs Vaccination, Study Finds

Navya Voleti, DO

A study from Penn State College of Medicine is providing new insight into the comparative risk of myocarditis following a COVID-19 infection compared with vaccination.

A systematic review and meta-analysis of data from 22 studies with data from 58 million individuals, results of the study suggest the relative risk of developing myocarditis was more than 7 times greater among those with a COVID-19 infection than those who underwent vaccination.

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

With each passing month of the COVID-19 pandemic, a seemingly new concern regarding the impact of comorbidities on disease severity or prognosis surrounding post-COVID recovery seemed to emerge. Although many of these concerns have been addressed or fallen out of the public eye, the issue of myocarditis risk following COVID-19 infection and vaccination has persisted as a point of discussion.

With an interest in further exploration of the topic, Voleti and a team of colleagues at Penn State Health designed a systematic review and meta-analysis with the specific intent of compare the incidence of myocarditis in COVID-19 vaccines and in COVID-19 infection groups. With this in mind, investigators used the MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, WHO Global Literature on Coronavirus Disease, and multiple trial registries up to May 2022 for randomized controlled trials and observational cohort studies reporting risk of myocarditis associated with COVID-19 vaccines and the risk associated with COVID-19 infection.

From their search, investigators identified 22 studies consisting of 55.5 million vaccinated individuals and 2.5 million with a documented COVID-19 infection. Of the 22 studies included, 10 assessed myocarditis rates from infection and 12 assessed myocarditis rates from COVID-19 vaccines. The overall study cohort had a median age of 49 (IQR, 38-56) years and 49% (IQR, 43-52%) were men.

Upon analysis, results indicated the relative risk for myocarditis was more than 7 times greater among those in the COVID-19 infection group compared to those in the vaccine group (RR, 15 [95% CI, 11.09-19.81] vs RR, 2 [95% CI, 1.44-2.65]). Further analysis indicated 61% of cases of myocarditis were among men, with meta-regression analysis suggesting men and younger populations had an increased risk of myocarditis. Additionally, investigators noted a slow decline in rates of myocarditis as a function of time from vaccination.

“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 lead investigator Paddy Ssentongo, MD, PhD, a resident physician in the Department of Medicine at Penn State Health Milton S. Hershey Medical Center, in the aforementioned statement. “We hope our findings will help mitigate vaccine hesitancy and increase vaccine uptake.”

This study, “Myocarditis in SARS-CoV-2 infection vs. COVID-19 vaccination: A systematic review and meta-analysis,” was published in Frontiers in Cardiovascular Medicine.