Several European countries have either suspended inoculations with the AstraZeneca Covid vaccine as a precautionary measure or banned the use of a specific batch after after blood clots formed in some people who had received the jab.
Both the Anglo-Swedish drugmaker and Europe’s medicines regulator said the vaccine was safe as Denmark, Norway and Iceland announced on Thursday they were temporarily halting all AstraZeneca vaccinations to investigate the cases.
Italy’s national medicines authority, meanwhile, followed Austria, Estonia, Latvia, Luxembourg and Lithuania in banning inoculations with one particular batch of AstraZeneca vaccines, consisting of 1m doses, which was sent to 17 countries.
The European Medicines Agency said this week that 22 cases of blood clots had been reported as of 9 March among more than 3 million people vaccinated with the AstraZeneca shot in Europe. There was no evidence so far linking AstraZeneca to the two cases in Austria, it said on Wednesday.
AstraZeneca, which developed the vaccine with the University of Oxford, said the safety of its shot had been extensively studied in human trials and that peer-reviewed data had confirmed the vaccine was generally well tolerated.
Its vaccines were subject to strict and rigorous quality controls and that there had been “no confirmed serious adverse events associated with the vaccine”, it has said.
The British government defended the vaccine and said it would continue with its own rollout. “We’ve been clear that it’s both safe and effective … and when people are asked to come forward and take it, they should do so in confidence,” the official spokesman of the prime minister, Boris Johnson, told reporters.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, told Reuters that the decision to suspend the shots was “a super-cautious approach based on some isolated reports in Europe”.
The problem with “spontaneous reports of suspected adverse reactions to vaccines is the enormous difficulty of distinguishing a causal effect from a coincidence”, Evans said, adding that Covid-19 was strongly associated with blood clotting.
Denmark’s national health agency said it was suspending AstraZeneca vaccinations for two weeks because a 60-year-old woman, who was given an shot from the same batch as used in Austria, formed a blood clot and subsequently died.
The agency said it had not established a link between the clots and the vaccine, but had asked regional authorities in charge of the vaccination programme to stop using the AstraZeneca shot pending consultations with the national medicines regulator.
Søren Brostrøm, the agency’s director, said it needed “to respond promptly and carefully when we have knowledge of possible serious side-effects. We need to clarify this before we can continue using the AstraZeneca vaccine.”
Brostrøm said there was “broad documentation proving that the vaccine is both safe and effective”, stressing: “We have not terminated the use of the AstraZeneca vaccine, we are just pausing its use.”
The Danish health minister, Magnus Heunicke, said on Twitter: “It is currently not possible to conclude whether there is a link. We are acting early, it needs to be thoroughly investigated.”
Norway was suspending use of the vaccine “as a cautionary decision” after the Danish announcement, Geir Bukholm, the director of infection prevention and control at the Norwegian institute of public health, said. “We await information to see if there is a link between the vaccination and this case with a blood clot,” he said.
Italy’s health authority said it was banning the use of the suspect batch after being notified of “some serious adverse effects”, but stressed the move was precautionary and no link had been established with the vaccine.
Media reports said two police officers in Sicily, aged 43 and 50, had died as a result of “severe coagulation disorders” after reportedly being inoculated with doses from the batch 12 days ago. Prosecutors have launched an investigation.
Austria stopped using the batch on Monday when a 49-year-old nurse died of “severe blood coagulation problems” days after receiving an anti-Covid shot. Spain said on Thursday it had not registered any cases of blood clots related to the vaccine and would continue administering the shots.
Danish media said the suspension meant people who have had an initial shot of the Anglo-Swedish vaccine would not receive a second jab for the time being and all AstraZeneca vaccination slots had been cancelled.
More than 142,000 people in Denmark have received a first shot of the AstraZeneca vaccine, according to figures from the state Serum Institut. The prime minister, Mette Frederiksen, said the news was “of course regrettable, because we are so incredibly dependent on everyone being vaccinated”.
Denmark has been ahead of most of the rest of the EU27 with its vaccination programme and has already administered a first dose to about 13% of its population, prioritising care home residents, over-65s receiving daily help, healthy people aged over 85, healthcare workers, and people with underlying conditions that mean they are particularly at risk from infection.