Study by Providence researchers on post-vaccination myocarditis/pericarditis reinforces safety of COVID-19 vaccine

Although the incidence of myocarditis or pericarditis post-vaccination is very rare, these results will help physicians be aware of the timing of the condition after vaccination and reassure patients that heart inflammation after vaccination generally resolves.

RENTON, Wash., August 5, 2021 – Providence, one of the largest health systems in the nation, published findings today, that demonstrate the rarity of myocarditis and pericarditis occurring post COVID-19 vaccination. The findings align with a similar pattern to CDC reports, at a slightly higher incidence.

The research published in the Journal of the American Medical Association found that of 2 million individuals receiving at least one COVID-19 vaccination, just 20 had vaccine-related myocarditis and 37 had pericarditis. Looking at the individuals who did develop one of the syndromes, the data provided key information for physicians. The researchers found that myocarditis developed rapidly in younger patients, mostly after the second vaccination, while Pericarditis affected older patients later, after either the first or second dose.

“These findings are significant because they provide another data point on the safety of the COVID-19 vaccines. They show that the incidence of heart inflammation from the vaccine is extremely low and provide physicians with helpful information on monitoring patients post-vaccination. I hope this new data incentivizes patients who are not yet vaccinated to get the vaccine,” said the study’s lead author George Diaz, MD, Medical Director, Antimicrobial Stewardship and Infection Prevention at Providence.

Providence cares for 5 million patients per year. Researchers examined vaccinated patients who subsequently had emergency department (ED) or inpatient encounters with diagnoses of ‘myocarditis’, ‘myopericarditis’ or pericarditis’. All information is anonymous. The data showed the following:

Myocarditis

• Myocarditis occurred 3.5 days post-vaccination, four patients developed symptoms after the first vaccination, and 16 after the second. Average age of patient is 36
• Nineteen patients were admitted to the hospital, and all were discharged with no re-admissions or deaths.
• Two patients received a second vaccine after onset of myocarditis and neither worsened.

Pericarditis

• Pericarditis developed after the first or second immunization, and the median onset was 20 days from most recent vaccination. Average age of patient is 59.
• Thirteen patients were admitted, none to intensive care, with a median stay of one day and no patient deaths.
• Pericarditis may be more common than myocarditis among older patients.

With this information, physicians can be better informed on monitoring and tracking patients after receiving the COVID-19 vaccine and can be assured that heart inflammation related to vaccination, while rare, typically resolves within roughly three weeks.

About Providence 
Providence is a national, not-for-profit Catholic health system comprising a diverse family of organizations and driven by a belief that health is a human right. With 52 hospitals, over 1,000 physician clinics, senior services, supportive housing, and many other health and educational services, the health system and its partners employ more than 120,000 caregivers serving communities across seven states – Alaska, California, Montana, New Mexico, Oregon, Texas, and Washington, with system offices in Renton, Wash., and Irvine, Calif. Learn about our vision of health for a better world at Providence.org.