AstraZeneca's coronavirus vaccine increases the risk of one type of thrombosis, British scientists who published a new study in the journal PLoS Medicine say. The scientists analyzed 21 million Britons who received two doses of vaccination between December 2020 and March 2021. They then compared the information with data from unvaccinated Britons, as well as with pre-pandemic thrombosis statistics. Analysis of all these data showed that only elderly patients were at risk of vascular congestion and thrombocytopenia. In addition, the AstraZeneca vaccine can cause only one type of thrombosis, the one that affects intracranial veins. As the results of the study showed, vaccination with this drug increased the likelihood of thrombosis in the head vessels by about 2.2 times. Such a problem was not detected in unvaccinated citizens, nor was it common with the Pfizer vaccine.