A new study, published today in Nature Communications, reveals that the incidence of heart attacks and strokes was significantly lower after the COVID-19 vaccination. This observational study, involving nearly the entire adult population of England, has sparked substantial controversy and debate regarding the broader implications of the COVID-19 vaccination on public health.

The study, conducted by the Universities of Cambridge, Bristol and Edinburgh and supported by the British Heart Foundation (BHF) Data Science Centre at Health Data Research UK, analysed anonymized health data from 46 million adults in England.The period studied spans from December 8, 2020, to January 23, 2022, covering the first two years of the COVID-19 vaccination program.

 The study found a marked reduction in the incidence of arterial thromboses, including heart attacks and strokes, post-vaccination. Specifically, these events decreased by up to 10% in the 13 to 24 weeks following the first dose of the COVID-19 vaccine. After the second dose, this reduction was more pronounced, with incidences up to 27% lower following the AstraZeneca vaccine and up to 20% lower following the Pfizer/BioNTech vaccine. Venous thrombotic events, such as pulmonary embolism and lower limb deep venous thrombosis, also showed a similar decrease.

 “We studied COVID-19 vaccines and cardiovascular disease in nearly 46 million adults in England and found a lower incidence of common cardiovascular diseases, such as heart attacks and strokes, following each vaccination than before or without vaccination,” said Dr. Samantha Ip, co-first author and Research Associate at the University of Cambridge. Dr. Samantha Ip, co-first author and Research Associate at the University of Cambridge, said, "This research further supports the large body of evidence on the effectiveness of the COVID-19 vaccination program, which has shown to provide protection against severe COVID-19 and save millions of lives worldwide."

 However, the study's findings have not been without controversy. Previous research indicated a higher incidence of rare cardiovascular complications following certain COVID-19 vaccines. For example, myocarditis and pericarditis have been linked to mRNA-based vaccines like Pfizer and BioNTech, while vaccine-induced thrombotic thrombocytopenia has been associated with adenovirus-based vaccines such as AstraZeneca. This latest study upholds the earlier findings and underscores the absence of any new adverse cardiovascular conditions, thereby confirming the superiority of vaccination over its risks.

 Professor William Whiteley, Associate Director at the BHF Data Science Centre and Professor of Neurology and Epidemiology at the University of Edinburgh, addressed these concerns: “This England-wide study offers patients reassurance of the cardiovascular safety of first, second, and booster doses of COVID-19 vaccines. It demonstrates that the benefits of second and booster doses, with fewer common cardiovascular events including heart attacks and strokes after vaccination, outweigh the very rare cardiovascular complications.”

In a secure data environment that NHS England provided, the researchers used de-identified, linked data from GP practices, hospital admissions, and death records. This comprehensive approach enabled a robust analysis of the impact of COVID-19 vaccination on cardiovascular health.

Dr. Venexia Walker, co-author and Research Fellow at the University of Bristol, highlighted the importance of continued research: “Given the critical role of COVID-19 vaccines in protecting people from COVID-19, it is important we continue to study the benefits and risks associated with them. The availability of population-wide data has allowed us to study different combinations of COVID-19 vaccines and consider rare cardiovascular complications. Without the large data we have access to and our close cross-institution collaborations, this would not have been possible

Despite the positive findings, the study also noted that the incidence of cardiovascular disease is higher after COVID-19, particularly in severe cases. This could partly explain the lower incidence of heart attacks and strokes in vaccinated individuals, suggesting that vaccination not only protects against COVID-19 but also reduces the likelihood of severe cardiovascular events in those who do contract the virus. We need further research to fully understand these mechanisms and their long-term implications.