Why European have suspended AstraZeneca vaccine

The decisions are centered on concerns about a rare type of brain clot.

In the past few days, Germany, Italy, Spain, Ireland and France became some of the latest countries to suspend the use of AstraZeneca’s coronavirus vaccine. They say they want time for the European Medicines Agency, the European drug regulator, to assess new data after a number of new blood-clotting incidents emerged.

Several of them had initially said they would keep using the vaccine, developed by Oxford University and British-Swedish pharmaceutical firm AstraZeneca, despite earlier suspensions by Norway and Denmark over blood-clot concerns. Their decisions to change course have sparked fierce debate in the scientific community.

In Britain, where 11 million doses of the vaccine have been administered, Prime Minister Boris Johnson has said he sees no reason to discontinue using it. AstraZeneca has fought back against the suspensions, saying there is no proven link between its vaccine and the blood clots, and the World Health Organization has assured its safety, but European regulators are carrying out a review based on new clotting reports. The Oxford-AstraZeneca vaccine has not been approved for use in the United States, but doses have been bought.

So what caused the flurry of suspensions?

María Jesús Lamas, the director of the Spanish Medication Agency, said her country’s thinking changed during the weekend. “From Saturday to Sunday, we were made aware of a case of cerebral venous thrombosis, specifically of the venous sinuses, which developed with a reduction in platelets, which implies irregular coagulation activity,” she told the Spanish newspaper El Pais. “Fortunately, [the patient] is recovering, but that same day we found out about three similar cases in Norway, and Germany had also identified four cases. We decided that this accumulation of cases of this particular and specific thrombosis warranted additional evaluation.”

By Monday, Germany, which had also initially said it would stick with the vaccine after suspensions from Norway and Denmark, said it had found seven cases of cerebral venous sinus thrombosis, a blood clot in a key vein in the brain, among those who had received the 1.6 million doses of AstraZeneca administered in the country. Its medical regulator reversed its position and said it recommended a suspension, citing the “accumulation of a special form of very rare cerebral vein thrombosis” connected to a lack of blood platelets and bleeding close to vaccinations with the Oxford-AstraZeneca vaccine.

French officials have linked their decision to the German data. On Tuesday, Alain Fischer, the French government’s top vaccine adviser, defended the decision to suspend the vaccine’s use, citing a “small number of unusual side effects.”

What are the risks?

As it carries out its urgent review, the European Medicines Agency says that thousands of people develop blood clots for various reasons and that overall numbers don’t seem to be a concern. “The number of thromboembolic events overall in vaccinated people seems not to be higher than that seen in the general population,” it said, adding that a “rigorous analysis” of all the data will be carried out in coming days.

AstraZeneca says there is “no evidence” that cases of blood clots are linked to the vaccine and that there have only been 37 reports of blood clots out of more than 17 million people vaccinated in the European Union and Britain.

Britain’s regulator says it is monitoring the situation, but people should still go out and get their vaccine.

“We are closely reviewing reports but given the large number of doses administered, and the frequency at which blood clots can occur naturally, the evidence available does not suggest the vaccine is the cause,” said Phil Bryan, vaccines safety lead at the Medicines and Healthcare products Regulatory Agency, according to the BBC.

But in Germany, the concern is that the seven cases of the more rare cerebral blood clots in a 1.6 million-dose vaccination program that has lasted a month and a half does appear higher than normal. Johns Hopkins Medicine says CVST normally affects about five people in 1 million each year.

Germany’s health ministry said that between 1 and 1.4 cases of these rare clots would be expected among the vaccinated group of people within a period of 14 days after getting a shot, so the seven cases is well above that, leading its authorities to conclude that this is more than “would be expected statistically.” It has declined to comment on whether any of those seven cases were fatal.

The European regulator says that while overall rates of blood clots in those vaccinated are not higher than normal, its review will focus on reports of elevated levels of these rarer type of clots. “This is a serious concern, and it does need serious scientific evaluation," said Emer Cooke, the executive director of the EMA. She said experts in blood clots are making urgent assessments as to whether there is a link between the vaccine and the blood clots in the brain.

Crucially though, she stressed that given thousands of people across Europe are dying each day, the agency is still of the belief that the benefits of the vaccine outweigh the risks.

What does it mean for the fight against the coronavirus?

The decisions come against the background of a sluggish vaccine rollout in Europe. If the suspensions are upheld, they will put European countries that are relying on the easier to administer AstraZeneca jab to relieve pressure on their intensive care units and their return to normalcy even further behind. Several countries in Europe are warning that they are in the midst of a third wave. In Germany, just over 8 percent of people have had a first vaccine dose, compared with more than 40 percent in the United Kingdom.

Even if the suspensions are lifted, they will have further damaged vaccine confidence in Europe, where AstraZeneca already was struggling with an image problem. Initial confusion over trial data and dosing and efficacy rates had led to reports of some AstraZeneca vaccine appointments not being taken up.

In the Irish Mirror on Tuesday, Irish biochemist Luke O’Neill said he was disappointed with the country’s suspension of the Oxford-AstraZeneca vaccine. While the vaccine has not been linked to blood clots, the coronavirus has, he said.

“And even worse, we know the virus itself causes blood clots — there is a high risk of that — so they are putting 30,000 people at risk now who aren’t getting vaccinated this week, so I think it is very disturbing to be honest,” he said.

The EMA’s Cooke said that the agency is mindful of the potential damage to vaccine confidence and is therefore making its assessment as quickly as possible. It says it will report results of its review on Thursday. In response to whether there was a political element to suspensions in post-Brexit Europe, Cooke said that the urgent review was based on nothing but scientific concerns.

“We are worried that there may be an effect on the trust in the vaccines, but our job is to make sure that the products that we authorize are safe,” she said.