“Our conclusion is that these coagulation disorders are very rare side effects of the vaccine,” said Sabine Straus, chair of the EMA’s evaluation committee. She said the conclusion was based on incident rates and scientific investigation, as the organization said an immune response after vaccination is the “likely” cause of the blood clots.
So far, most of the reported cases have occurred in women under 60, the regulator said, but it said it has still not been able to train if certain groups were more vulnerable than others.
But when officials spoke, Britain became the latest European country to adjust its vaccination guidelines, saying adults under the age of 30 should be offered an alternative to the home-made vaccine developed in collaboration with Oxford University.
AstraZeneca did not immediately respond to a request for comment on Wednesday, but said that safety remains its top priority and that it is analyzing its databases with tens of thousands of patients to better understand whether there is a higher rate of blood clots than otherwise. expected.
The vaccine has been under intense scientific control since the beginning of last month, when a 49-year-old nurse died of complications due to blood clots following her vaccination in Austria. Other cases followed across Europe, leading some countries to suspend their use of the vaccine until scientific studies were conducted.
Concerns are centered on a rare condition called cerebral venous sinus thrombosis or CVST, a blood clot that prevents blood from draining from the brain. Regulators have said it occurs among those vaccinated at a rate above what they would expect to see in the normal population.
A total of 169 cases of CVST have been reported among 34 million people who received AstraZeneca across Europe as of April 4, the EMA said. In addition, there have been 52 other cases of rare blood clots. It said it based its scientific review on an initial 62 cases and 18 deaths until March 22, but continued reports did not change their assessment.
Wednesday’s announcement is the latest blow to the vaccine, which was hailed as a key tool to lead the world out of the pandemic. Cheap and easier to store than others on the market. There are plans to roll it out in more than 140 countries through a program designed to ensure fair distribution.
Researchers are still trying to figure out if certain sections of the population are at increased risk. The UK has documented the severe blood clots in about 1 in 500,000 shots. However, higher rates in countries that only started using AstraZeneca’s vaccine among younger people have spurred the debate on whether the risk may be higher for certain age groups or for women. The EMA has estimated the risk for people under 60 to about 1 in 100,000. It said the majority of blood clots have occurred in women under that age, but they are not yet able to say with certainty whether it is because they are at higher risk or whether more young women have been vaccinated.
In Germany, 29 out of 31 patients with cerebral thrombosis have been women. But the European regulator has said it may be because countries like Germany started vaccinating communities as health workers that include more women.
The EMA said the majority of blood clots have occurred in women under 60 years of age. Whether the risk outweighs the benefits of the vaccine for sections of the population as younger women: “At the moment, it’s something that is very difficult to answer,” Straus said.
In the UK, regulators essentially recommend that, if possible, those under the age of 30 should receive the Pfizer or Moderna vaccine, if available, instead of taking AstraZeneca jab.
The UK vaccine advisory body and drug regulators said the evidence “reinforced” that the AstraZeneca shot may have caused these very rare blood clots.
June Raine, head of the Medicines and Healthcare Products Regulatory Agency, said that by the end of March, more than 20 million people in the UK had received at least one dose of AstraZeneca. Of these, a review found that 79 people suffered rare blood clots after a dose of vaccine: 51 women and 28 men. 19 of these people died. And three of those 19 were under 30 years old.
Raine said 4 out of a million people may have died as a result of a blood clot from the AstraZeneca vaccine.
Health officials stressed that the investigation into the causal link between vaccination and blood clots was ongoing and not yet final.
They stressed that for most people – especially the elderly – it is far better to get a safe and effective vaccine than not. British officials said they made new recommendations based on an “abundance of caution.”
“This is a course correction,” said Jonathan Van-Tam, England’s deputy chief medical officer, at a televised briefing. He compared Britain’s rapid and relatively successful vaccine campaign to a sea lining. “If you’re sailing a massive liner across the Atlantic, it’s not really fair that you won’t have to make at least one course correction in that voyage,” Van Tam said. He called the chances of anyone – including young people – getting a blood clot from the AstraZeneca vaccine as “vanishingly small.”
“This vaccine has been shown to be extremely effective in preventing serious illness and hospitalization, and it saves lives,” said EMA Director Emer Cooke. “Vaccination is extremely important to help us in the fight against covid-19, and we need to use the vaccines.
Booth reported from London.