The blood clots linked with AstraZeneca-Oxford’s COVID-19 vaccine are seen in between just one and three cases per million, according to a study published in the journal PLOS Medicine.

The study scrutinized health records of 46 million adults in England between December 2020 and March 2021 to assess the risk of clots in the month after vaccination with both the Pfizer-BioNTech vaccine and the AstraZeneca-Oxford jab compared with the unvaccinated population.

The risk of intracranial venous thrombosis after getting the AstraZeneca-Oxford vaccine was almost twice that in those under age 70. The study, which showed that the blood clots occurred only after the first dose, found no risk of major arterial and venous thrombotic events in those 70 or over with either of the vaccines.