Clinical observations show acute myocarditis developed after mRNA COVID-19 vaccination

By James DuckerReviewed by Emily Henderson, B.Sc.Jun 29 2021

Four patients suffering from acute myocarditis after mRNA COVID-19 vaccination suggests that further investigation is needed to determine associations of vaccination and myocarditis.

Preliminary diagnoses linking mRNA COVID-19 vaccination and acute myocarditis

Vaccine-associated myocarditis is extremely rare but has been described previously in patients administered with the smallpox vaccine and has otherwise received only anecdotal reports for other vaccinations.  

For instance, across all 416 629 adults in the Vaccine Safety Datalink that received live measles, mumps, and rubella; varicella; oral polio; or yellow fever viral vaccinations, no patients with myocarditis in the 42 days following vaccination.

With the recent advent of the COVID-19 pandemic, recent vaccination efforts have been implemented on global scales.

A new clinical report from the Duke Cardiovascular Magnetic Resonance Center in Durham, North Carolina, shows novel cases of acute myocarditis following mRNA COVID-19 vaccination.

The report follows patients suffering from acute myocarditis and specifically examined patients that had been vaccinated prior to hospitalization in North Carolina.

4 of the 7 patients that showed symptoms post-vaccination were aged between 23 and 70 years old and presented severe chest pain as well as biomarker evidence of myocardial injury.

The patients were hospitalized and had cardiac magnetic resonance imaging findings typical of myocarditis. The diagnosis of acute myocarditis 5 days after the vaccination suggests that patients experienced symptoms as potential side effects from having the vaccine administered.  

Therefore, the clinical report provides the first evidence of a potential link between mRNA COVID-19 vaccination and acute myocarditis.

Myocarditis. Image Credit: BlurryMe/Shutterstock.com

Addressing limitations and the requirement for more research

Despite the findings of the report, it is particularly important to consider that the comparative sample size, regional scale, and analysis has yet to show a broad associative pattern between COVID-19 mRNA vaccination and myocarditis.

Expanding the number of patients diagnosed as well as the breadth of analysis may provide better information and possible links to conditions caused by the vaccination. This report is done on an annual basis to determine the number of individuals affected by acute myocarditis, so further research is therefore required to establish more conclusive findings.

Nonetheless, although causality cannot be established, the results of this report raise the possibility of an association between mRNA COVID-19vaccination and acute myocarditis.