Study: COVID-19 Vaccination Not Associated With Increased Risk of Heart Attack, Stroke

COVID-19 vaccination is not associated with an increased risk of heart attack or stroke in individuals with established cardiovascular disease, according to a large study published in Cardiovascular Research.

“Our study showed that pre-existing cardiovascular disease should not prevent people from getting vaccinated against COVID-19,” Esther Chan, BPharm (Hons), PhD, FSHP, of the Li Ka Shing Faculty of Medicine at The University of Hong Kong, said in a statement. “Vaccination is particularly important for this group since cardiovascular disease is associated with worse outcomes and a higher risk of death after COVID-19 infection.”

This study was the first to examine the association between COVID-19 vaccines and the risk of major adverse cardiovascular events (MACE) in individuals with cardiovascular disease, according to the authors. It included the BNT162b2 and CoronaVac vaccines, which are the only COVID-19 vaccines authorized for emergency use in Hong Kong.

Investigators used data from electronic health records managed by the Hong Kong Hospital Authority, which covers approximately 80% of hospital admissions and vaccination records provided by the Hong Kong Department of Health, according to a university press release.

The first 2 doses were analyzed by investigators and the individuals were not permitted to switch between vaccine types for the first 2 doses. Each individual was compared with themselves for the risk of MACE up to 27 days after each vaccination dose compared to the non-exposure baseline period.

“A traditional cohort study would compare the vaccinated group with the unvaccinated group but the two groups could have different baseline characteristics. A self-controlled case series avoids the issue of differences between groups since each individual acts as his/her own control,” Chan said in a statement.

Investigators included a total of 229,235 individuals with cardiovascular disease, of whom 1764 were vaccinated and experienced MACE during the study period of February 23, 2021, to January 31, 2022.

Existing cardiovascular disease included coronary heart disease, cerebrovascular disease peripheral vascular disease, and prior interventions, such as stenting. MACE included myocardial infarction, stroke, revascularization, or cardiovascular death.

For BNT162b2 and CoronaVac, investigators estimated the incidence rate ratios (IRR) to compare the risk of MACE during the 13 days after vaccination versus the baseline period. IRR was also calculated for the risk of MACE during days 14 to 27 post-vaccination compared to the baseline period.

Investigators found that there was no new evidence of an elevated risk of MACE after the first or second dose of BNT162b2 or CoronaVac.

For the first dose of BNT162b2, the IRRs were 0.48 during the first 13 days post-vaccination and 0.4 during days 14 to 27 days after vaccination. For the second dose, the IRRs were 0.87 during the first 13 days and 1.13 during days 14 to 27 after vaccination.

For the first dose of CoronaVac, the IRRs were 0.43 during the first 13 days and 0.54 during days 14 and 27 post-vaccination. For the second dose, the IRRs were 0.73 for the first 13 days and 0.83 during days 14 to 27 days after vaccination.

Chan said that the findings were consistent for women and men, as well individuals who were under and above 65 years of age. The same was true for individuals with different underlying cardiovascular conditions.

Reference

COVID vaccines are safe for patients with cardiovascular disease. EurekAlert. News release. June 22, 2022. Accessed June 28, 2022. https://www.eurekalert.org/news-releases/956505