Regulators have found a link between AstraZeneca's COVID-19 shot and rare blood clots in younger women, but the exact cause of the clots is unknown, a top official said
- A European official said Tuesday there was a link between AstraZeneca's COVID-19 vaccine and blood clots.
- Marco Cavaleri, head of vaccines at the EMA, said the mechanism causing the brain blood clots wasn't yet clear.
- The clots are most common in younger women, he said.
The European medicines regulator has found a link between AstraZeneca's COVID-19 vaccine and rare blood clots in younger women, an official said Tuesday.
The exact cause of the rare brain clots in vaccinated people was not yet known, Marco Cavaleri, head of vaccines at the European Medicines Agency (EMA), told Italian newspaper Il Messagero.
The very rare cases of blood clots were associated with a low platelet count, and were most common in women, he said.
Cavaleri said that the average age of people getting the clots following vaccination was between 45 and 47 years-old. There were some cases in women older than 50, and about 20% of cases were in men, he said.
The EMA is this week expected to provide an update on its investigation into rare blood clots in people who have received AstraZeneca's vaccine.
Emer Cooke, the EMA's executive director, said in a press briefing Wednesday that a "causal link" between rare blood disorders and AstraZeneca's vaccine was not proven, but that it was "possible."
The EMA has received 62 reports worldwide of a rare brain blood clot in vaccinated people. More than 9 million people had been vaccinated with AstraZeneca's shot as of March 22, amounting to 1 case in 100,000, with most cases in women under 60, the regulator said Wednesday.
Read more: COVID-19 Vaccine Tracker: AstraZeneca's shot proves safe and effective, and is headed to the FDA
So far, at least nine countries have restricted the use of AstraZeneca's vaccine, pending the EMA's decision. Norway and Denmark have fully suspended the shot, while France and Canada have stopped giving it to under 55s. Germany has stopped giving it to anyone under 60.
Cavaleri said that the EMA would not set age restrictions for the vaccine. Instead, it would provide precise information about the vaccine's benefits and risks, some of which were already included in the EMA's March 18 update, he said
Countries can then make their own decision about the vaccine's rollout.
Cavaleri added that the benefits of AstraZeneca vaccine in preventing COVID-19, with its associated risk of hospitalization and death, still outweigh the risks of side effects, a view that the EMA has maintained in recent weeks.