Studies in Denmark and Norway show that the proportion of venous thrombosis in people who received the first dose of AstraZeneca’s COVID-19 vaccine, including blood clots in the brain, was slightly higher than the expected proportion of the general population. I found that it was increasing.
However, the researchers who conducted the study emphasized that such side effects are extremely rare and that the benefits of the vaccine outweigh the risks in most situations.
“The absolute risk of venous thromboembolism described in this study is small, and the findings should be interpreted in the context of the benefits of COVID-19 vaccination at both the social and individual levels,” they said. Wrote in the summary of the findings. It was published in the BMJ Medical Journal on Thursday.
Norway suspended the deployment of the AstraZeneca vaccine on March 11, after a small number of cases of blood clots with bleeding and decreased platelet count. Denmark has also withdrawn the use of shots.
Medical regulators in Europe and the United Kingdom state that vaccines are safe and effective, and their benefits far outweigh the risks of side effects, but in some other countries they are used only in certain age groups. It is recommended to do.
The BMJ study surveyed 280,000 people aged 18-65 years in Denmark and Norway who received their first dose of the AstraZeneca vaccine between early February and March 11.
Using national health records, researchers identified the incidence of events such as heart attack, stroke, deep vein thrombosis, and bleeding events within 28 days of receiving the first vaccination with Denmark. Compared to the expected incidence of the general population of Denmark. ..
The results show 59 blood clots intravenously compared to the expected 30, which corresponds to 11 excess events for every 100,000 vaccinations. Researchers said this included a higher than expected rate of rare cerebral thrombosis known as cerebral venous thrombosis, at 2.5 cases per 100,000 vaccinations.
Paul Hunter, a professor of medicine at the University of East Anglia in the United Kingdom, commented on the findings, saying he had a better understanding of the risk of thrombosis after COVID-19 vaccination, but that regulators’ conclusions should not be changed. ..
“Countries that delayed their vaccination programs during periods of high infection by refusing to use available (AstraZeneca) vaccines decided that their decision would increase the avoidable deaths from COVID-19. You should know that you have contributed, “he said. ..
Kate Keland