The AstraZeneca coronavirus vaccine is “safe and effective” and its benefits outweigh the risks, Europe’s medicines regulator has said, but it will continue to study possible links between the shot and a very rare blood clotting disorder.
The director of the European Medicines Agency (EMA), Emer Cooke, said the agency’s safety committee had reached “a clear scientific conclusion” and had not found that the vaccine was associated with an increase in the overall risk of blood clots.
But Cooke said the agency’s review, launched after about 30 cases of unusual clotting and low platelet counts in recipients of the vaccine prompted more than a dozen EU countries to suspend its use, had uncovered “a small number of cases of rare and unusual but very serious clotting disorders”.
She said the EMA still could “not rule out definitively a link between these cases and the vaccine”, and was therefore recommending “to raise awareness” of possible risks.
A new warning in the vaccine information would draw attention to “possible rare conditions” to help recipients and healthcare professionals “prevent and mitigate any possible side effects”, she said.
Starting a third wave driven by more infectious new variants and struggling to accelerate sluggish inoculation programme, several EU countries responded rapidly to the news. Italy’s prime minister, Mario Draghi, said AstraZeneca vaccinations would resume on Friday, and Spain is set to make a similar announcement later on Thursday.
“We have vaccines that can prevent death and hospitalisation – we need to use them,” Cooke said. “A lot of member states are waiting for the outcome of this safety review. Countries can now make an informed decision so as to the safety of the vaccine.”
Austria, the Baltic states, Denmark, France, Germany, Ireland, Italy, the Netherlands, Portugal, Spain and Sweden, along with non EU-member Norway, are among the European countries to have either paused the vaccine or banned specific batches.
Investigations were continuing into the rare events, Cooke said, but “about seven million people have now been vaccinated in the EU with the AstraZeneca vaccine, and 11 million in the UK … I want to reiterate that our scientific position is that this vaccine is a safe and effective option to protect citizens against Covid-19”.
She said the agency’s investigation had not uncovered any problems related to specific batches of the shot or manufacturing sites. “If it was me, I would be vaccinated tomorrow,” she said. “But I would want to know what to do if I had any problems – and that’s what we’re doing now.”
Britain’s MHRA medicines regulator also said on Thursday that the evidence did not suggest that the AstraZeneca vaccine caused blood clots, adding that it too was still investigating a very rare and specific type of blood clot in cerebral veins.
MHRA said there had been five cases of cerebral venous sinus thrombosis (CVST) combined with a low platelets count in recipients of the shot in the UK, and there was no need to pause the shot.
A British expert, Prof Sir Munir Pirmohamed, chair of the Commission on Human Medicines, said even if a link between CVST and the shot was found, it was unlikely the UK vaccination campaign would be halted since the incidence rate was so low.
Norway’s expert group said on Thursday that after investigating three health workers who had fallen ill with the same combination of CVST and low platelet counts, one of whom died, they believed a strong immune reaction to the vaccine was the cause.
“We have no other history in these patients that could give such a strong immune response,” Prof Pål Andre Holme said. “I am absolutely certain it is these antibodies that are the cause and see no other reason than … the vaccine that triggers it.”
The World Health Organization’s global vaccine safety panel is currently examining the vaccine data and the precise clinical circumstances of each rare blood coagulation case, the body said, and will publish its findings on Friday.
AstraZeneca has said 17 million people in the EU and UK have received the vaccine and the number of cases of blood clots reported “is lower than the hundreds of cases that would be expected among the general population”.
Denmark, the first to suspend the shot last week after a 60-year-old woman died from a “highly unusual” blood event, and Germany, where three recipients have died from the rare cerebral vein thrombosis, have said they acted on strictly scientific grounds.
Because of the extreme rarity of the events, the decision to pause the shot has been criticised as political. Some EU members states such as Belgium and Greece did not suspect, with Belgium saying pausing the vaccine was “irresponsible”.
The AstraZeneca vaccine was already perceived by many in the EU as second-best after several national agencies postponed its authorisation for the over-65s over of a lack of data. Experts fear the suspensions may further depress its take-up.