The possible side effects of the AstraZeneca vaccine come into sharper focus

LONDON For months, European countries have seen the way out between the desired will and the rejection of the AstraZenecas vaccine, with the fate of the shots rising and falling over supply points and questions about the effectiveness of the vaccine itself.

But few concerns have been proven to disrupt the distribution of working horse vaccines worldwide in Europe, as blood clotting reports are very rare in some recipients. Many countries responded by banning the use of shots, only to start giving it back after a clear adjustment by regulators at the European Medicines Agency and then banning inoculations a second time in certain age groups as doctors became more concerned for clots.

On Tuesday, those concerns were reinforced again when a senior vaccine official at the European Medicines Agency said the vaccine was linked to extremely rare, though sometimes fatal, blood clots in a small number of recipients. It was the first indication from an international regulator that clots could be a real, if very unusual, side effect of the shock.

Regulators now appear to be considering issuing their first official warnings about possible side effects not only in continental Europe, which has long been wary of hitting for political and scientific reasons, but also in Britain, the birthplace of the vaccine. AstraZeneca and during the biggest champion, where new data have sown concerns as well.

The University of Oxford, which developed the vaccine with AstraZeneca, said on Tuesday it had suspended a two-month vaccine trial in children and adolescents in Britain while awaiting regulatory guidance.

Immediate concerns are threatening to spread around the world and disrupt the global spread of a cheap and easy-to-maintain vaccine, one that remains the best hope of many countries to save lives amid a widespread increase in cases of coronavirus. At least 94 countries with different income levels have administered doses.

Most scientists and health officials say the benefits of vaccines still outweigh the risks in older people, who seem less susceptible to clots. Dozens of cases of blood clots, mostly among young people, have been reported among the tens of millions of people who have received the vaccine across Europe.

But more countries may limit the use of vaccines to young people, trying to inoculate enough people to reopen economies at war. The European Medicines Agency said it would meet this week to consider updating its guidelines.

This agency and the World Health Organization have said that no causal link between the vaccine and clots has been proven and advised that stroke suspension would cost more than it would save.

Regulators in Britain, where the goal is the backbone of the fast inoculation site program, have also insisted that the benefits of vaccines outweigh the risks. They and the company cited a lack of evidence in Britain that coagulation events were more common than expected among people who had never received the AstraZenecas vaccine.

But the evidence changed last week when Britain reported 30 cases of infrequent blood clotting, 25 more than before. This week, a prominent scientific adviser to the British government said there was growing evidence of clots associated with the vaccine.

AstraZeneca did not comment on Tuesday.

However, news reports indicated that British regulators were considering updating their guidelines for its use in young people, who are believed to be more sensitive to side effects.

No vaccine, no medicine is safe, said government science adviser Neil Ferguson, an epidemiologist at Imperial College London. He added that British regulators were considering the issue very urgently.

For the AstraZeneca vaccine, recent concerns have added a new chapter to a turbulent spread in Europe. In Germany, health officials initially broke away from European regulators in mid-February and recommended that the stroke be given only to adults under 65, citing insufficient clinical trial data on its effectiveness in the elderly. As a result, most of the Germans who first got the vaccine were medical workers and teachers, many of them women.

This may be one reason why potential side effects appeared more rapidly in Germany and elsewhere in Europe than in Britain, where the vaccine first spread among older people and has only recently been administered to younger age groups. .

On March 15, Germany’s health minister announced that the country was suspending the use of the stroke, due to blood clotting issues. Health officials reversed the course after European regulators determined that the risk was so low that it would be more dangerous to keep the vaccine.

Last week, Germany came back again, recommending that no one under the age of 60 get the vaccine. Since then, the Netherlands has followed suit. Other countries, such as France and Canada, have also suspended vaccine use among young people. Norway and Denmark have completely stopped while they investigate.

Believed to be more common in younger women, the cases are an unusual condition in which clots combine with extremely low platelet levels, a disorder that can lead to bleeding.

The vaccine appears to be triggering an immune response in which antibodies bind to platelets, activating them, Andreas Greinacher, a German doctor leading an investigation at the University of Greifswald, told a news conference Wednesday.

For their part, platelets were causing the formation of dangerous clots in certain parts of the body, including the veins that drain blood from the brain, leading in some cases to a rare type of stroke.

Why exactly the vaccine was creating those antibodies remained unclear. He said there was no evidence that pre-existing conditions had certain people assigned to the side effects.

What we can say clearly is that the complications of thrombosis are related to these antibodies, said Dr. Greinacher, referring to clots.

Doctors and health officials seem to be growing more confident that blood clots were a genuine, though still unexplained, response from a very small number of people to the AstraZeneca vaccine.

European regulators were analyzing 44 cases of rare brain clots, 14 of them fatal, out of 9.2 million people vaccinated across Europe. For people under 60, who make up the majority of cases, that translates to a risk of one in 100,000, said Emer Cooke, European director of Medicines Agencys.

In Britain, regulators reported 30 cases of rare blood clots combined with low platelets among the 18 million people given the AstraZeneca vaccine. This translates to approximately one case in 600,000 vaccine recipients.

Divergent approaches to vaccine in European countries stem from a number of factors, including the supply of vaccines and the severity of the pandemic. Marco Cavaleri, an official at the European Medicines Agency who spoke about the link between the vaccine and blood clots, said on Tuesday that these factors were likely to continue to dictate how countries used the stroke.

Beyond these factors, countries also took very different approaches to risk management, scientists said. Countries that continued to use the stroke were more focused on ensuring the overall health of their citizens. Others were more concerned with minimizing the risk to every single person.

Stay here is more, Get me out of the pandemic, said Penny Ward, a visiting professor of pharmaceutical medicine at Kings College London, referring to the British approach. In continental Europe, she said, there seems to be a higher emphasis on individual security in the population.

Adriano Mannino, a philosopher at the University of Munich and director of the Solon Center for Policy Innovation in Germany, said the collective benefits of the vaccine outweighed thinking in Britain, while Germans were more concerned about the risk of an injection going bad in individual cases. . This reflected, in part, the history of Germany with the Nazis, who carried out deadly experiments on humans.

In many areas where the law must regulate delicate and potentially dangerous ethical things, he said, the German state has attempted to impose tough restrictions.

However, for Germans over the age of 60, the age group still underwent the AstraZeneca vaccine, flooded the hotlines to book appointments and stood in line for hours in recent days, as eligibility restrictions for their age group had eased.

In the northeastern city of Wismar, several hundred people waited up to five hours Tuesday in a gust of wind and a mixture of rain and snow to take the hit.

I wish there was a better time, Kerstin Weiss, head of the district authority in the Northeast region, told public broadcaster NDR. But honestly, this is a sign that people are ready to be vaccinated with AstraZeneca.

Benjamin Mueller reported from London and Melissa Eddy from Berlin. Monika Pronczuk contributed with reporting from Brussels and Emma Bubola from Rome.