New study of 46-million adults in England confirms blood clot risk with COVID-19 vaccine is very small

Press release issued: 22 February 2022

The risk of blood clots after COVID-19 vaccinations is very low finds a new study of 46-million adults in England. The research, which involved University of Bristol academics, showed that people vaccinated with Oxford-AstraZeneca or Pfizer-BioNTech had a lower risk of all venous clots (such as deep vein thrombosis and pulmonary embolism) and all arterial clots (such as strokes and heart attacks), particularly in people over 70 years.

The research team found that 1–3 extra people per million had an intracranial venous thrombosis after the Oxford-AstraZeneca vaccine, but that there was no evidence that these rare blood clots were associated with the Pfizer-BioNTech vaccine.

Read the full University of Bristol press release

Paper: Whiteley WN et al. (2022). Association of COVID-19 vaccines ChAdOx1 and BNT162b2 with major venous, arterial, or thrombocytopenic events: A population-based cohort study of 46 million adults in England. PLOS Medicine.