Study: Cardiac complications more common after COVID-19 infection than vaccination

Editor's Note

In a Morbidity and Mortality Weekly Report from the Centers for Disease Control and Prevention, an analysis of electronic health records (EHR) from 40 US health systems showed that the risk of developing myocarditis and other inflammatory heart conditions after COVID-19 vaccination is “substantially lower” than it is after COVID-19 infection, JAMA Network May 24 reports.

Myocarditis has been associated with both COVID-19 infection and mRNA vaccines, JAMA notes. In this study, the investigators analyzed EHR data of 15.2 million people and calculated incidence rates of:

• myocarditis
• myocarditis or pericarditis
• myocarditis, pericarditis, and multisystem inflammatory syndrome.

The data was pulled from early January 2021 through January 2022, with the purpose of comparing the likelihood of developing any of the above complications post-infection versus post-vaccination.

Here are the highlights:

• Men aged 12 to 17 years: incidence of myocarditis or pericarditis after infection was about twice as high as after 2 doses of mRNA vaccination.
• Men aged 18 to 29 years had a 7 to 9 times greater risk of cardiac complications after infection than after 2 doses of vaccine.
• Women aged 12 years or older: the risk of cardiac complications ranged from 6 to 63 times higher after infection than after 2 doses of an mRNA-based vaccine.

Incidence of myocarditis after vaccination was zero or close to it in children, making a statistically significant comparison virtually impossible, the investigators noted.