Dear Dr. Roach: I recently got a blood transfusion, and I’ve never had the COVID vaccine. Am I going to get those blood clots that vaccinated people got? — Anon.
Answer: There is no evidence of risk to people receiving blood from a donor who received any COVID vaccine.
Both the Astra-Zeneca vaccine and the Janssen vaccine did have a very small number of cases of abnormal blood clots (about four cases per million recipients). The much more commonly used mRNA vaccines made by Moderna and Pfizer-BioNTech did not cause an increase in blood clotting.
