Syringes are filled with Astrazeneca’s vaccine in the pharmacy.
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LONDON – Europe’s drug regulator has identified a possible link between the coronavirus vaccine developed by AstraZeneca and Oxford University and rare blood clotting problems.
Abnormal blood clotting with low platelets is added to the vaccine product information as a “very rare” side effect, along with a number of other possible side effects, said Emer Cooke, executive director of the European Medicines Agency, in a televised news conference Wednesday.
The warning comes after the regulator’s safety committee reviewed extremely rare cases of unusual blood clots in some people vaccinated with the Oxford-AstraZeneca shot. Most cases occurred in women under 60 within two weeks of the shot. The EMA has not yet identified any specific risk factors that contributed to this phenomenon.
The researchers also don’t know what specifically causes the blood clots, but one plausible explanation is that the vaccine elicits an immune response in some people that is similar to that seen in patients treated with heparin, known as heparin-induced thrombocytopenia, said Cooke.
“This case clearly shows one of the challenges posed by large-scale vaccination campaigns,” she said. “When millions of people receive these vaccines, very rare events that have not been identified in clinical trials can occur.”
Separately, the UK Medicines Agency announced on Wednesday that it had also identified a possible link between the shot and the rare blood clots. The Medicines and Health Products Regulator (MHRA) also said the benefits of Oxford-AstraZeneca’s vaccine outweighed the risks for most people.
The UK’s Joint Committee on Vaccination and Immunization said people under the age of 30 who have no health problems should get a different vaccine if possible.
Other side effects
The EMA, reporting other possible side effects, added that it was “of great importance” that health professionals and those receiving the Oxford-AstraZeneca vaccine are aware of the risks and watch out for possible symptoms that are typical occur in the first two weeks after inoculation.
“These include, for example, shortness of breath, chest pain, swelling in the leg, persistent abdominal pain, neurological symptoms such as severe or persistent headaches or blurred vision and skin bruises beyond the injection site,” said Dr. Sabine Straus, chair of EMA’s security committee, said at the same press conference. These side effects are listed in the vaccine’s product information as possible adverse drug reactions, she said.
AstraZeneca’s shares closed around 1% in London.
Professor Jonathan Van-Tam, the UK’s Deputy Chief Medical Officer, described the country’s new Oxford-AstraZeneca vaccine council as a “course correction” for the UK
The MHRA, the body that approved it for use in the UK, examined the data following reports – in both the UK and continental Europe – of serious but rare blood clots, some of which were fatal.
A UK study of the Oxford AstraZeneca vaccine in children has already been paused while the drug agency investigated a possible link between the shot and the bleeding disorders, particularly cases of blood clots in veins in the brain known as cerebral venous sinus thrombosis (CVST) as well Thrombocytopenia (low levels of platelets in the blood that help blood to clot).
The UK government found that as of March 24th, there were 22 reports of CVST and eight reports of other low platelet thrombosis events totaling 18.1 million doses of the AstraZeneca vaccine (one shot with two doses). given up to this date.
Ongoing security concerns
The Oxford-AstraZeneca shot has been followed by safety concerns in recent weeks, and several European countries temporarily stopped using the vaccine last month.
The EMA said on March 31 that it had found the shot to be safe and effective, but added that it could not rule out the possibility of a causal link between the vaccine and coagulation events, so the investigation will continue.
The World Health Organization, the UK Medicines Agency and the International Society on Thrombosis and Hemostasis have all stated that the benefits of administering the Oxford-AstraZeneca shot far outweigh the risks.
People are waiting in a vaccination center in Cologne on April 5, 2021.
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AstraZeneca previously said that its studies didn’t find a higher risk of blood clots as a result of its vaccine.
Most countries have since resumed the use of the shot, but many have suspended vaccinations for certain age groups.
The EMA had denied any known link between the Oxford-AstraZeneca shot and rare blood clots before Tuesday when a senior European Medicines Agency reported a clear “link” between the Oxford-AstraZeneca vaccine and very rare blood clots in the brain.
In an interview with the Italian newspaper Il Messaggero published on Tuesday, Marco Cavaleri, chairman of the EMA’s vaccine evaluation team, said: “In my opinion, we can now say that there is a link to the vaccine, but we are still me don’t know what is causing this reaction. “
– CNBC’s Holly Ellyatt contributed to this report.