EU Regulator: AstraZeneca Vaccine Effective; Blood clots can be a rare side effect

Updated April 7, 2021, 11:52 a.m. ET

The European Union’s medicines regulator said on Wednesday that the benefits of AstraZeneca’s COVID-19 vaccine outweigh its risks, but rare blood clotting events should be listed as a possible side effect.

The European Medicines Agency’s assessment comes after a panel of experts examined reports of unusual blood clots occurring in some vaccine recipients. Officials stressed that these events are rare and said that although they appear to be more common in women under the age of 60, there is not enough evidence available to confirm specific risk factors such as l age, gender or medical history.

They said it was important for healthcare providers and the public to be aware of the signs and symptoms of these unusual events – which include shortness of breath, persistent abdominal pain and swelling in the legs – and that information about the vaccine product will be updated to list them. as a possible adverse reaction. They still recommend its use and pointed out that the vaccine has been shown to prevent serious illness, hospitalizations and death.

“The risk of death from COVID is much greater than the risk of death from these side effects,” said Emer Cooke, executive director of the European Medicines Agency. “I think it’s important that we send the message that vaccines will help us in the fight against COVID, and we need to keep using these vaccines. ”

In a declaration, the agency said healthcare professionals and vaccinees should be aware of the “possibility of very rare cases of blood clots associated with low levels of blood platelets occurring within 2 weeks of vaccination.”

The regulator’s pharmacovigilance risk assessment committee noted that the recorded blood clots occurred in the veins of the brain and abdomen, and in the arteries, combined with low levels of blood platelets and “bleeding.” sometimes “.

As of Sunday, the European Union’s Medicines Safety Database had recorded 169 cases of blood clots in the brain, also known as cerebral venous sinus thrombosis, and 53 cases of those in the abdomen, or splanchnic vein thrombosis, in the European Economic Area and the United States. UK – where some 34 million people had received the vaccine.

Dr Sabine Straus, chair of the committee, said there was a “probable causal association” between the rare clots and the vaccine. It is too early for the European Medicines Agency to identify a precise cause of the rare disease, conclusively determine risk factors or recommend specific measures to reduce the risk, officials said.

They noted that a plausible explanation for the combination of blood clots and low blood platelets is an immune response triggering a condition similar to that seen occasionally in patients treated with the anticoagulant. heparin.

The agency said it would continue to monitor cases and issue further recommendations if necessary. He also commissioned further research from AstraZeneca.

“This case clearly demonstrates one of the challenges of large-scale vaccination campaigns,” Cooke said. “When millions of people receive these vaccines, very rare events can occur that have not been identified in clinical trials.”

But it also shows that the region’s pharmacovigilance system is working, she said, as unusual events could be quickly identified, analyzed and dealt with.

The UK Medicines and Health Products Regulatory Agency has also published results Wednesday establishing a “possible link” between the AstraZeneca vaccine and extremely rare blood clots.

He said the benefits of the sting continued to outweigh any risk, but advised that “careful attention” be given to people at higher risk of specific types of blood clots due to a medical problem. .

He did not recommend age restrictions in the use of the vaccine, but the UK Joint Committee on Vaccination and Immunization noted on the same day when it would be preferable, where possible, for adults under 30 without an underlying condition to be offered an alternative.

“We do not advise stopping any vaccination for any individual of any age group,” Wei Shen Lim, COVID-19 chair of that committee, said in a briefing, according to Reuters. “We are advising a preference for one vaccine over another vaccine for a particular age group, really out of the utmost caution, rather than because we have serious safety concerns.”

Last month, there were reports of dozens of blood clots that occurred after the vaccination, including several fatalities. This prompted more than a dozen countries, mainly in Europe, for to suspend temporary use of the AstraZeneca vaccine, although the European Medicines Agency and World Health Organization both continued to recommend its use.

Many of these countries resumed vaccines after an investigation by the European Medicines Agency last month found that the benefits of the vaccine far outweigh its risks, with officials noting that the number of “thromboembolic events” reported after vaccination was actually lower than expected in the general population.

The regulator announced the March 18 that its preliminary investigation had determined that the vaccine was safe and effective, and stated that there was no increase in the overall risk of blood clots associated with its use, although some questions remained.

Several of the countries that have resumed vaccinations against AstraZeneca have done so under conditions; for example, the French health authorities are recommend only for people aged 55 and over, Germany suspended The “common use” of the vaccine for people under the age of 60 and South Korea said on Wednesday he would temporarily deny the vaccine to people under the age of 60.

And Tuesday, the University of Oxford announcement he was suspending a small trial in the UK that would test the vaccine on individuals aged 6 to 17 while awaiting more data on blood clotting reports.

The AstraZeneca vaccine has been approved by many countries around the world, and its affordability – at just $ 4 a dose – and minimal handling requirements make it ideal for global use, as NPR reported.

WHO approved in February that the vaccine for emergency use be deployed worldwide through COVAX, an international effort to help low- and middle-income countries fight the pandemic. And the Biden administration said last month it was finalizing plans to lend million doses in Mexico and Canada.

It is not currently used in the United States. The company said it would look for emergency use clearance from the U.S. Food and Drug Administration, making it the fourth coronavirus vaccine available in the country.

This process also raised some questions after an independent watchdog said the company released data showing an incomplete picture of its effectiveness. AstraZeneca then released results showing slightly decreased efficacy figures: 76% efficacy against symptomatic COVID-19 and 100% efficacy against serious or critical illness and hospitalization.

Dr Anthony Fauci, chief medical adviser to the Biden administration, said Reuters earlier this month, the United States may not need it to immunize the entire population.

“My general feeling is that given the contractual relationships we have with a number of companies, we have enough vaccines to meet all of our needs without relying on AstraZeneca,” Fauci said.

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