AstraZeneca Vaccine Carries Slightly Higher Risk of Bleeding Disorders, Study Shows

But the research, involving 2.53 million adults in Scotland, found that the vaccine’s benefits outweighed the small risks.

People receiving the Covid vaccine made by Oxford-AstraZeneca had a slightly increased risk of a bleeding disorder, and possibly other rare blood problems, researchers reported on Wednesday. The findings, from a study of 2.53 million adults in Scotland who received their first doses of either the AstraZeneca vaccine or the one made by Pfizer-BioNTech, were published in the journal Nature Medicine. About 1.7 million of the shots were the AstraZeneca vaccine. The study found no increased risk of the blood disorders with the Pfizer-BioNTech vaccine.