Director Heart Failure Program St Michael's Hospital St. Michael's Hospital Toronto, Ontario, Canada
Background: We previously demonstrated that the 30-day mortality rate following COVID-19 infection was significantly higher in Chinese individuals, lower in South Asian individuals, compared to the general Ontario population. COVID-19 vaccines are protective against SARS-CoV-2-related diseases. It is, however, unclear whether vaccination uptake rates, and post-vaccination myocarditis/pericarditis risk, are similar between ethnicity groups.
METHODS AND RESULTS: We conducted a population-based, retrospective cohort study using linked health administrative datasets from Ontario to compare COVID-19 vaccination uptake rates, and myocarditis/pericarditis rates in those vaccinated, among the Chinese, South Asian, and general populations. These populations were identified using a surname-based algorithm. The cohort was defined on December 1, 2020, to coincide with COVID-19 vaccine availability, and were followed until June 30, 2022, for first and second dose vaccination. Myocarditis/pericarditis hospital admissions and emergency department visits within 42 days post-vaccination were analyzed. For the first dose, vaccination uptake was highest in the general population during the first 120 days. Afterwards, Chinese and South Asians had greater vaccine uptake compared to the general population. A similar pattern was observed for the second dose. Post-vaccine myocarditis/pericarditis rates were lower among Chinese (19.6 per 1,000,000 first doses) and South Asians individuals (20.86 per 1,000,000 first doses) compared to the general population (51.37 per 1,000,000 first doses), with similar findings following the second dose; differences statistically significant. However, the standardized morbidity ratios, comparing observed vs. expected myocarditis/pericarditis rates post-vaccination, were similar across the Chinese, South Asian, and general populations.
Conclusion: For the COVID-19 vaccine, there is differential uptake and post-vaccination myocarditis/pericarditis among the Chinese and South Asian populations in Ontario. These findings can help inform the design of future research and health delivery program.
