Researchers from the Universities of Cambridge, Bristol and Edinburgh have suggested that COVID-19 vaccinations could lower the incidence of arterial thromboses.
The study, published in Nature Communications, was supported by the British Heart Foundation (BHF) Data Science Centre at Health Data Research UK.
Researchers analysed the de-identified health records of 46 million adults from GP practices, hospital admissions and death records in England between December 2020 and January 2022, provided by NHS England.
The team compared the incidence of cardiovascular diseases (CVDs) following COVID-19 vaccination with the incidence before or without vaccination during the first two years of the vaccination programme.
CVD affects around seven million people in the UK and is a significant cause of disability and death.
Overall, the study revealed that the incidence of arterial thromboses, such as heart attacks and strokes, which affect 200,000 people in the UK every year combined, was up to 10% lower in the 13 to 24 weeks after the first dose of COVID-19 vaccine. Following a second dose, the incidence increased to a 27% lower incidence after receiving the AstraZeneca vaccine and up to 20% lower following the Pfizer/BioNtech vaccine.
Additionally, the incidence of venous thrombotic events, such as pulmonary embolism and lower limb deep venous thrombosis, demonstrated a similar pattern.
Researchers believe that the incidence of heart attacks and strokes is lower in vaccinated people compared to unvaccinated people because CVD is higher after COVID-19, and suggest that “the benefits of second and booster doses…. outweigh the very rare cardiovascular complications,” explained professor William Whiteley, associate director, BHF Data Science Centre and professor of neurology and epidemiology, University of Edinburgh.
Co-first author Dr Samantha Ip, research associate, department of public health and primary care, University of Cambridge, said that findings from the study “further supports the large body of evidence on the safety of the COVID-19 vaccination programme, which has… provided protection against severe COVID-19 and saved millions of lives worldwide”.

https://www.cam.ac.uk/research/news/incidence-of-heart-attacks-and-strokes-was-lower-after-covid-19-vaccination