Patients fully vaccinated against COVID-19 are less likely to experience acute myocardial infarction (MI) or ischemic stroke following COVID-19 infection compared with unvaccinated individuals, according to a study published in the Journal of the American Medical Association.
Researchers conducted a retrospective cohort study using the Korean National Health Insurance Service database and the Korean national registry on COVID-19 vaccination and infection between July 2020 and December 2021. They analyzed the incidence of ischemic stroke and acute MI within 31 to 120 days following COVID-19 infection in fully vaccinated (2 doses of mRNA vaccines or viral vector vaccine) compared with unvaccinated adults against SARS-CoV-2, aged 18 years or older.
For the study, the researchers compared individuals never vaccinated (n=62,727) with individuals fully vaccinated against COVID-19 (n=168,310). Patients who were fully vaccinated were more likely to be older and have more comorbidities. However, these individuals were less likely to experience severe or critical COVID-19. Both the unvaccinated and the fully vaccinated groups had about an equal amount of women (52% vs 53%).
Between day 31 and 120, 31 unvaccinated patients and 74 fully vaccinated patients experienced either an ischemic stroke or acute MI, resulting in an incidence rate of 6.18 vs 5.49 per 1,000,000 person-days.
The vaccinated group demonstrated significantly lower risk for either acute MI or ischemic stroke compared with the unvaccinated group (adjusted hazard ratio [aHR], 0.42, 95% CI, 0.29-0.62; P <.001).
When comparing the adverse events separately, incidence rates for only acute MI remained lower in the fully vaccinated group compared with the unvaccinated group (aHR, 0.48; 95% CI, 0.25-0.94; P =.03). Similarly, incidence rates for only ischemic stroke also remained lower in the fully vaccinated group (aHR, 0.40; 95% CI, 0.26-0.63; P <.001).
A limitation of the study included potential errors in diagnosis codes used for outcome events.
The researchers concluded that “The findings support vaccination, especially for those with risk factors for cardiovascular diseases.”
Kim YE, Huh K, Park YJ, Peck KR, Jung J. Association between vaccination and acute myocardial infarction and ischemic stroke after COVID-19 infection. JAMA. Published online July 22, 2022. doi:10.1001/jama.2022.12992