Higher Incidence of Myocarditis, Pericarditis Found After COVID-19 Vaccination

Despite evidence of a higher risk of myocarditis or pericarditis with COVID-19 vaccination, immunization should still be recommended because the benefits likely outweigh the harms, study shows.

A recent study found a higher incidence of myocarditis or pericarditis in patients following COVID-19 vaccination, which was greater following the second dose compared with the first dose; however, the study noted that the risk for these conditions is significantly lower than the health risks seen in patients with COVID-19, highlighting the need for a risk-benefit analysis in certain patients. The increased incidence of pericarditis or myocarditis was noted mainly in those who received BNT162b2 and mRNA-1273 vaccines and no increased risks were found in other types of COVID-19 vaccines.

“Compared to those who did not receive COVID-19 vaccine, those who received either the first or second dose had a significantly increased risk of myocarditis or pericarditis,” the study authors wrote. “In addition, those who received the second dose of COVID-19 vaccine had a higher risk of myocarditis/pericarditis compared with those who received only the first dose of COVID-19 vaccine.”

Myocarditis is inflammation in the cardiac muscle that is most frequently caused by viral disease, Symptoms include chest pain, fever, life-threatening congestive heart failure, and arrhythmias. Acute pericarditis is the most common form of pericardial disease and frequently involves severe chest pain behind the sternum.

Following the launch of COVID-19 vaccines, reports emerged of potential negative cardiovascular effects post immunization. Despite safety and immunogenicity tests showing positive results, clinical evidence on the safety and efficacy of the currently approved COVID-19 vaccines is limited, according to the authors of the current study.

“The majority of the data were obtained from relatively small populations and over relatively short periods,” the study authors wrote. “Therefore, the adverse reactions from the vaccine are of concern. It has been reported that the most common local adverse reactions include pain and swelling.”

The investigators sought to establish the risk of myocarditis/pericarditis post COVID-19 vaccination by conducting an extensive meta-analysis of published studies. The researchers performed a systemic literature search in 7 online databases by March 31, 2022, and tested heterogeneity by I2 index.

The analysis included 11 studies with 58,620,611 subjects in which COVID-19 vaccination correlated with an increased risk of myocarditis or pericarditis. The study showed a greater risk of myocarditis or pericarditis in individuals who received the second dose of COVID-19 vaccine compared with those who only received the first dose of the COVID-19 vaccine.

Compared to unvaccinated individuals , myocarditis or pericarditis after COVID-19 vaccines were 2.13-fold higher (95% CI=1.55, 2.94; I2= 92.5%; p<0.001). There was also a statistically significant association found between COVID-19 vaccination and myocarditis with a pooled RR of 2.02 (95% CI=1.21, 3.37; I2=97.8%; p<0.001). This association was not found in pericarditis (RR=1.16; 95% CI=0.74, 1.82; I2=0; p=0.509).

“It is noteworthy that although an increased risk of pericarditis was not found, only 2 studies of pericarditis were included in the analysis, therefore, the result on pericarditis risk needs to be interpreted with caution. Nevertheless, the potential mechanisms of association between COVID-19 vaccination and myocarditis or pericarditis remains uncertain,” the study authors wrote.

Compared with the first dose of a COVID-19 vaccine, the administration of the second dose was associated with a greater risk of pericarditis and/or myocarditis, with a pooled RR of 4.06 (95% CI=2.08, 7.92; I2=52.5%; p<0.001).

Although the higher risk of myocarditis and pericarditis being higher among those administered the COVID-19 vaccine, it the authors noted that myocarditis or pericarditis was predominantly mild in these individuals. They added that the spontaneous resolution of vaccine-associated myocarditis is common.

“The clinical trial results of the COVID-19 vaccine showed a very good safety profile, however, the sample size of the trial was not large enough to detect the rare adverse events that may occur. In addition, some studies have shown that the incidence of myocarditis or pericarditis resulting from vaccination is much lower than that in people infected with COVID-19,” the study authors wrote. “Despite the meta-analysis results suggesting a higher risk of myocarditis or pericarditis with COVID-19 vaccination, vaccination should still be recommended because benefits of the vaccine likely outweigh its harms. More importantly, adjustment of vaccination strategies to reduce the incidence of adverse events based on monitoring data from the vaccine adverse event system is needed if necessary.”

REFERENCE

Gao J, Feng L, Li Y, et al. A Systematic Review and Meta-analysis of the Association Between SARS-CoV-2 Vaccination and Myocarditis or Pericarditis. September 25, 2022. Accessed November 3, 2022. https://doi.org/10.1016/j.amepre.2022.09.002