RESUMO
This study evaluates 21-day risk of myocarditis/pericarditis following COVID-19 vaccination among those aged 12 years and older in Malaysia. We used data from nationwide COVID-19 vaccine registry linked to hospital episode database to identify individuals vaccinated with BNT162b2, CoronaVac, or ChAdOx1 and hospitalised for myocarditis/pericarditis between 1 February 2021 and 28 February 2022. There were 87 myocarditis/pericarditis cases identified within 1-21 days after vaccination. Most cases were reported following BNT16262 vaccination (77.0%) with absolute risk of 0.33 cases/100,000 vaccinated persons or 1.73 per million doses administered. Highest risk was observed following second dose and in younger, male individuals. The risk of myocarditis/pericarditis following CoronaVac and ChAdOx1 were much lower compared to BNT162b2. The findings on higher risk observed among younger following mRNA vaccine were consistent with literature and important for targeted surveillance.
RESUMO
BACKGROUND: Rapid deployment of COVID-19 vaccines is challenging for safety surveillance, especially on adverse events of special interest (AESIs) that were not identified during the pre-licensure studies. This study evaluated the risk of hospitalisations for predefined diagnoses among the vaccinated population in Malaysia. METHODS: Hospital admissions for selected diagnoses between 1 February 2021 and 30 September 2021 were linked to the national COVID-19 immunisation register. We conducted self-controlled case-series study by identifying individuals who received COVID-19 vaccine and diagnosis of thrombocytopenia, venous thromboembolism, myocardial infarction, myocarditis/pericarditis, arrhythmia, stroke, Bell's Palsy, and convulsion/seizure. The incidence of events was assessed in risk period of 21 days postvaccination relative to the control period. We used conditional Poisson regression to calculate the incidence rate ratio (IRR) and 95% confidence interval (CI) with adjustment for calendar period. RESULTS: There was no increase in the risk for myocarditis/pericarditis, Bell's Palsy, stroke, and myocardial infarction in the 21 days following either dose of BNT162b2, CoronaVac, and ChAdOx1 vaccines. A small increased risk of venous thromboembolism (IRR 1.24; 95% CI 1.02, 1.49), arrhythmia (IRR 1.16, 95% CI 1.07, 1.26), and convulsion/seizure (IRR 1.26; 95% CI 1.07, 1.48) was observed among BNT162b2 recipients. No association between CoronaVac vaccine was found with all events except arrhythmia (IRR 1.15; 95% CI 1.01, 1.30). ChAdOx1 vaccine was associated with an increased risk of thrombocytopenia (IRR 2.67; 95% CI 1.21, 5.89) and venous thromboembolism (IRR 2.22; 95% CI 1.17, 4.21). CONCLUSION: This study shows acceptable safety profiles of COVID-19 vaccines among recipients of BNT162b2, CoronaVac, and ChAdOx1 vaccines. This information can be used together with effectiveness data for risk-benefit analysis of the vaccination program. Further surveillance with more data is required to assess AESIs following COVID-19 vaccination in short- and long-term.