European medical regulators said Wednesday that the AstraZeneca vaccine is likely causing rare, but occasionally fatal, blood clots to a small percentage of those injected with the vaccine.
Officials have described the side effect as “very rare,” but emphasized it’s seriousness, nonetheless. They also stated that they need more time to investigate the link before coming to a definitive conclusion. Regulators said that as of Sunday there have been just over 200 cases of the clotting, out of the 34 million people who received the vaccine in the European Economic Area. They said that this puts the rate of the clotting at about one in 100,000 according the New York Times.
The European Medicines Agency, which regulated European drugs remain that people should still get the vaccine and that the overall benefits outweigh the possible risks. However, they recommend that health professionals and recipients should be cautious of symptoms like shortness of breath and swelling of the legs after the vaccine is administered.
“This case clearly demonstrates one of the challenges posed by large scare vaccination campaigns,” said the agency head Emer Cooke at Wednesday’s news conference. “ When millions of people receive these vaccines, very rare events can occur that were not identified during clinical trials.” He also said that “the risk of mortality from COVID is much greater than the risk of mortality from the side effects.”
When concerns about the clots were first released, many European countries restricted the use of the AstraZeneca vaccine to only those over 55 because they believed there may be a relationship between the adverse side effects and younger recipients. However, “the regulator said that it had not concluded that age or gender were a specific risk and that it would further investigate the issue.” Britain did however come out and adjusted their vaccination guidelines, now advising that adults under 30 should be offered a vaccine other than AstraZeneca’s.
The announcement comes after the vaccine had already been a source of controversy as incomplete data was found to be released earlier this month. This news has also adversely affected the larger “Covax” program which aims to make vaccines more widely available around the globe. AstraZeneca has been a cornerstone of this plan as the vaccine is cheaper and much easier to store and ship that others.
According to German doctors as well as the EMA, in the cases where the side effects happened the vaccine seemed to be causing an immune reaction where antibodies bind to platelets and activate them. These platelets then cause the formation of these sometimes-deadly clots in certain parts of the body. Doctors do not yet know why the antibodies develop in some people but they have speculated that it could be an excessive immune reaction. As of now, no pre-existing conditions have been found to make one more susceptible to clotting according to European health officials.