The chances of developing dangerous blood clots after being infected with the virus that causes Covid-19 far outweighs the risks of the AstraZeneca and Pfizer vaccines, according to the largest study of its kind.
The sweeping analysis used data from more than 29 million people in England to compare both vaccines with infection from Sars-Cov-2. It weighed up rates of hospital admission or death from blood clots, as well as other blood disorders, within 28 days of either a positive test or receiving the first jab.
Related:UK braces for Covid surge as people head to bank holiday hotspots
Lead author Julia Hippisley-Cox, professor of clinical epidemiology and general practice at the University of Oxford, said: “People should be aware of these increased risks after Covid-19 vaccination and seek medical attention promptly if they develop symptoms, but also be aware that the risks are considerably higher and over longer periods of time if they become infected with Sars Cov-2.”
