The safety and effectiveness of BNT162B2 and CoronaVac covid-19 vaccines in patients with cardiovascular disease

Abstract

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to a pandemic in 2019, affecting hundreds of millions of people globally. The infection of SARS-CoV-2 was reported to increase the risk of cardiovascular (CVD) comorbidities such as myocardial infarction (MI) and stroke, and it is important for patients with a history of CVD to receive the COVID-19 vaccines to prevent the potential severe outcomes. However, a series of adverse effects have caused worldwide vaccine hesitancy, especially for those with a history of CVD. Vaccine safety and effectiveness have been evaluated in randomized controlled trials (RCT) in the general population but very few patients with each type of CVD such as atherosclerotic cardiovascular disease (ASCVD), heart failure (HF) and atrial fibrillation (AF) were enrolled in these RCTs. Therefore, conducting observational studies in patients with each type of CVD is essential to further evaluate the safety of vaccines. Also, despite COVID-19 vaccines being reported to be effective in preventing SARS-CoV-2 infection in RCTs, the effectiveness waned, especially during the Omicron period. MI and stroke are the most serious CVD complications and although several vaccines were proven to be effective in preventing COVID-19-related mortality and hospitalization, whether they can also prevent MI and stroke after SARS-CoV-2 infection was unknown. Therefore, both the safety and effectiveness of the two available COVID-19 vaccines in Hong Kong, an mRNA vaccine BNT162b2 and an inactivated vaccine CoronaVac, were investigated in patients with CVD in this thesis. The findings of this thesis confirmed that there was no increased risk of major adverse cardiovascular event (MACE) after vaccination in patients with ASCVD, no increased risk of HF hospitalization, MACE and all hospitalization in patients with HF. There was, however, an increased risk of stroke or systemic embolism in female patients with AF but no increased risk of bleeding in all patients with AF. The increased risk identified only in female patients with AF showed the importance of examining vaccine safety in specific patient groups. However, as we detected an even higher risk of stroke or systemic embolism after COVID-19 infection, proactive uptake of COVID-19 vaccines is still recommended to prevent the potential severe outcomes after infection. A lower risk of MI and stroke after SARS-CoV-2 infection was observed in patients with CVD who received vaccination and there was a dose-response relationship, indicating that each additional subsequent dose was associated with a lower risk of severe CVD complications such as MI and stroke. Overall, it can be concluded that COVID-19 vaccines are important for patients with CVD to prevent potential severe outcomes if infected, but specific patient groups including female patients with AF should be aware of the risk versus benefits of vaccination. The findings of the research undertaken on COVID-19 vaccines in patients with CVD have broadened health professionals and the general public’s understanding of the vaccines’ safety and effectiveness profile to facilitate decision-making regarding vaccine uptake.