A recent study published in Heart has indicated that COVID-19 vaccines may significantly decrease the risk of heart failure and blood clots in veins or arteries for at least six months following SARS-CoV-2 infection. The study, conducted by University of Oxford investigators, analyzed electronic health records of 10.2 million vaccinated and 10.4 million unvaccinated COVID-naïve individuals from the United Kingdom, Spain, and Estonia between January and July 2021.
The research, which focused on the Alpha and Delta variants, included adults of all ages and those at high risk for severe COVID-19 outcomes. It encompassed all COVID-19 vaccines available in Europe at the time, namely AstraZeneca/Oxford, Pfizer/BioNTech, Johnson & Johnson (J&J), and Moderna. The study assessed various outcomes, such as ischemic stroke, myocardial infarction, heart failure, pulmonary embolism, and deep vein thrombosis.
Despite the effectiveness of COVID-19 vaccines in preventing infection, hospitalization, and death, concerns have been raised regarding rare blood clots following adenovirus-based vaccines (AstraZeneca and J&J) and a potential link between mRNA vaccines (Pfizer and Moderna) and a slight risk of myocarditis. On the other hand, SARS-CoV-2 infection has been associated with cardiac and thromboembolic complications, with the risk of serious complications remaining elevated for up to a year after infection.
The study revealed a 72% reduction in the risk of venous thromboembolism (VTE) at 3 to 6 months post-COVID-19 vaccination. Additionally, COVID vaccine effectiveness against heart failure, VTE, and arterial thrombosis/thromboembolism (ATE) was found to be 53%, 72%, and 61% at 3 to 6 months after SARS-CoV-2 infection.
Moreover, a comparison of Pfizer and AstraZeneca COVID-19 vaccines suggested a greater reduction in VTE with the former in the initial month after vaccination. Overall, the study emphasized the potential of COVID-19 vaccination in lowering the risk of post-COVID-19 cardiac and thromboembolic outcomes, particularly in the context of acute COVID-19 outcomes.
