Study Shows Safety of Hong Kong’s BNT162b2 and CoronaVac COVID-19 Vaccines for Patients With Cardiovascular Disease

June 23, 2022—The European Society of Cardiology (ESC) announced the publication of findings from a large study in Hong Kong demonstrating that COVID-19 vaccination with BNT162b2 (Pfizer BioNTech) or CoronaVac (Sinovac Biotech) is not associated with an increased risk of heart attack or stroke in patients with established cardiovascular disease.

According to ESC, this was the first study to examine the association between COVID-19 vaccines and the risk of major adverse cardiovascular events (MACE) in patients with cardiovascular disease. The study focused on BNT162b2 and CoronaVac, the only COVID-19 vaccines authorized for emergency use in Hong Kong.

The study, “Association between BNT162b2 or CoronaVac COVID-19 vaccines and major adverse cardiovascular events among individuals with cardiovascular disease,” was published by Xuxiao Ye, PhD (Candidate), et al in Cardiovascular Research, an official journal of the ESC.

Esther W. Chan, PhD, of the Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China, is the senior investigator of the study.

“Our study showed that pre-existing cardiovascular disease should not prevent people from getting vaccinated against COVID-19,” commented Dr. Chan in the ESC press release. “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.”

According to ESC, the study investigators linked 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. The first two vaccine doses were included in the analyses. Individuals were not permitted to switch vaccine types for the first two doses.

The investigators identified patients with existing cardiovascular disease and a new MACE diagnosis between February 23, 2021, when the mass COVID-19 vaccination program started in Hong Kong, and January 31, 2022. Established cardiovascular disease included coronary heart disease, cerebrovascular disease, peripheral vascular disease, and previous interventions such as stenting. MACE included myocardial infarction, stroke, revascularization, or cardiovascular death.

As summarized in the ESC press release, the investigators used the self-controlled case series study design, which was developed to assess the risk of adverse events after vaccination. Each patient was compared with himself/herself for the risk of MACE up to 27 days after each vaccine dose (exposure period) versus the nonexposure baseline period.

Dr. Chan explained in the ESC press release, “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.”

The investigators identified a total of 229,235 patients with cardiovascular disease; of those patients, 1,764 were vaccinated and experienced MACE during the study period (662 received BNT162b2 and 1,102 received CoronaVac).

For BNT162b2 and CoronaVac, the investigators estimated incidence rate ratios (IRRs) to compare the risk of MACE during the 13 days after vaccination compared to the baseline period. IRRs were also calculated for the risk of MACE during days 14 to 27 postvaccination versus the baseline period. The analyses were conducted for the first and second doses.

The ESC press release reported that there was no evidence of an elevated risk of MACE after the first or second dose of BNT162b2 or CoronaVac.

• For the first BNT162b2 dose, IRRs were 0.48 (95% CI, 0.23-1.02) during the first 13 days postvaccination and 0.40 (95% CI, 0.18-0.93) during days 14 to 27 days postvaccination.
• For the second BNT162b2 dose, IRRs were 0.87 (95% CI, 0.50-1.52) during the first 13 days and 1.13 (95% CI, 0.70-1.84) during days 14 to 27.
• For the first CoronaVac dose, IRRs were 0.43 (95% CI, 0.24-0.75) during the first 13 days and 0.54 (95% CI, 0.33-0.90) during days 14 to 27.
• For the second CoronaVac dose, the IRRs were 0.73 (95% CI, 0.46-1.16) for the first 13 days and 0.83 (95% CI, 0.54-1.29) during days 14 to 27.

Dr. Chan concluded in the ESC press release, “The findings were consistent for women and men, individuals aged under and above 65 years old, and patients with different underlying cardiovascular conditions. The results should provide reassurance about the cardiovascular safety of these two vaccines.”