Abstract
BACKGROUND: Evidence supporting the possible causal association of myopericarditis with the coronavirus disease (COVID-19) vaccine has mainly come from case reports. Epidemiological evidence indicating an increased relative risk for myopericarditis after COVID-19 vaccination is lacking. Therefore, this study aimed to identify and assess all confirmed COVID-19 vaccine- related cases of myopericarditis presenting to major cardiac centers in the Eastern Region of Saudi Arabia, before and after the introduction of the COVID-19 vaccine. METHODS: According to case definition, the hospital's information system database detected all confirmed cases at two main cardiac centers. RESULTS: Of the 18 confirmed myocarditis and myopericarditis cases detected after the administration of COVID-19 vaccines, three were possibly related to COVID-19 immunization. The first case was of myopericarditis following a third dose of mRNA-1273. The second case was myocarditis, which occurred seven days after the first dose of AstraZeneca. The third case was myocarditis, which occurred 12 days after the third dose of BNT162b2. A cardiologist carefully evaluated the cases using recognized protocols and case definitions to demonstrate a direct relationship with vaccination consequences rather than coincidence. CONCLUSION: We found no difference in the occurrence of myocarditis and myopericarditis after the COVID-19 vaccine compared with the background rate during a similar period (P = 0.9783). The incidences of myocarditis and myopericarditis following immunization were low. The advantages of the COVID-19 vaccination outweigh the risk of myopericarditis.