Rare blood clot events more common among women receiving AstraZeneca Covid-19 vaccine, EMA says
The EMA is sticking with its statement that AstraZeneca’s Covid-19 vaccine is safe and effective, but the agency also discussed new data showing that younger women are more frequently seeing these very rare cases of sometimes fatal blood clots when compared with the general population, although more women also received the vaccine than men.
EMA executive director Emer Cooke said Wednesday at a press conference that the agency’s safety committee is still reviewing the rare events, known as cerebral venous sinus thrombosis (CVST), which as of March 22, total 62 out of 9.2 million AstraZeneca vaccinations across the European Economic Area (EEA). Fourteen of those 62 cases were fatal, and 44 occurred in the EEA, she noted.
The total cases show that about 1 in 100,000 receiving the AstraZeneca vaccine are seeing these rare and severe events in Europe, although a causal or associative link between the vaccine and the events has not been established, according to Peter Arlett, head of the pharmacovigilance and epidemiology department at the EMA.
The number of rare events for the AstraZeneca vaccine also compares with less than 1 in 1 million for the Pfizer and Moderna vaccines each. But Cooke stressed that different groups and numbers of people have received each of the vaccines so it’s difficult to compare them.
The EMA’s safety committee, known as PRAC, will continue to review the data as it comes in on a daily basis and make another announcement on the AstraZeneca vaccine next week, Cooke noted, explaining that the EMA’s conclusion two weeks ago has not changed and the benefits of the AstraZeneca vaccine still outweigh the risks.
But cases of CVST are occurring at a higher rate among those under the age of 60 and receiving the AstraZeneca vaccine. Arlett added, “If we look at individuals under 60, then we do see more cases of cerebral venous sinus thrombosis than we would expect to see from the background.”
Cooke also noted a higher incidence among women between the ages of 30 and 45, when compared to the general population. CVST is more common in women in general, but about two-thirds of those receiving the AstraZeneca vaccine in Europe were women, Arlett added.
An AstraZeneca spokesperson told Endpoints News via email: “While the EMA reported that the PRAC’s investigation did show some predominance of cases in certain groups including younger women they said it is premature to draw any conclusions on that point right now. PRAC is currently assessing many possibilities including that the higher proportion of cases seen in young women may be due to a higher proportion of women vaccinated or a higher risk of thrombotic events in this population.”
The update from the EMA comes as Germany said it will stop using AstraZeneca’s vaccine on residents younger than 60. Several journalists questioned the EMA on the total of 62 CVST cases, noting that Germany alone has reported 31 cases, but Cooke said the 62 events do not account for all of the German cases and the EMA’s safety committee will look at newer figures before making its announcement next week.
Canada also recently said it would halt AstraZeneca shots for people 55 and younger, while Sweden and Finland are only using the vaccine for those over 65.
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