An Oxford University study found that the risk of rare but sometimes fatal blood clotting is about eight to ten times higher in people with Covid-19 than in people who have received any the first three vaccines developed in the West.
The study, which includes vaccines from Pfizer Inc. and BioNTech SE, another from Moderna Inc. and one from AstraZeneca PLC, is added to concurrent blood clotting-related tests that regulators and governments should consider as they weigh the continued deployment of vaccines.
U.S. officials have recommended a pause in the administration of a single-dose Covid-19 vaccine developed by Johnson & Johnson, as they are studying a possible link between the shot and a very small number of coagulation instances. severe blood. The Oxford study did not examine patient data from recipients of the J&J shot.
AstraZeneca has not been approved for use in the United States, but many governments across Europe have restricted it, amid several cases of similar blood clotting involving cerebral venous thrombosis, or TVC or CVST.
AstraZeneca has said it is helping regulators continue safety reviews and that the benefits of the vaccine outweigh its risks. J&J said he is aware of blood clot-related cases and works with health authorities.