Thromboembolism and the Oxford-AstraZeneca vaccine

Abstract

New study finds a link, but vaccination remains overwhelmingly the safest option Medicine regulators, health professionals, and the public are anxious to know whether the available vaccines against covid-19 are safe, and in particular whether the Oxford-AstraZeneca vaccine causes unusual thromboembolic events. In a linked paper, Pottegård and colleagues (doi:10.1136/bmj.n1114) compared observed rates of vascular and thromboembolic events in large cohorts of adults who received the Oxford-AstraZeneca vaccine in Denmark and Norway, with expected rates derived from the general populations of the same countries.1 They found that for arterial events, the number of observed outcomes was similar to that of expected (83 observed events v 86 expected), but people given the vaccine experienced more venous thromboembolic events than expected (59 observed v 30 expected). Seven of these events were cerebral venous thrombosis, a life threatening condition identified in recent weeks as a potential complication of the Oxford-AstraZeneca vaccine. Seven cases among 281 264 people vaccinated is a low absolute rate, but still 20 times the rate expected in the general population, and equivalent to …