Health authorities in Denmark, Iceland and Norway have temporarily suspended the use of AstraZeneca’s COVID-19 vaccine shots after reports of blood clots forming in some who receive it.
The move follows Austria’s halt to use of a batch of AstraZeneca shots while investigating a death from coagulation disorders and an illness from a pulmonary embolism.
Danish health authorities said the decision to suspend the shots for two weeks came after a 60-year old woman, who was given an AstraZeneca shot from the same batch used in Austria, formed a blood clot and died.
Danish authorities said they had responded “to reports of possible serious side effects, both from Denmark and other European countries”.
“It is currently not possible to conclude whether there is a link. We are acting early, it needs to be thoroughly investigated,” Health Minister Magnus Heunicke said on Twitter.
The vaccine will be suspended for 14 days in Denmark.
“This is a cautionary decision,” Geir Bukholm, director of infection prevention and control at the Norwegian Institute of Public Health (FHI), said.
FHI did not say how long the suspension would last.
“We … await information to see if there is a link between the vaccination and this case with a blood clot,” Mr Bukholm said.
Also on Thursday, Italy said it would suspend use of an AstraZeneca batch that was different to the one used in Austria.
Some health experts said there was little evidence to suggest the vaccine should not be administered and that the cases of blood clots corresponded with the rate of such cases in the general population.
“This is a super-cautious approach based on some isolated reports in Europe,” Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, told Reuters.
“The problem with spontaneous reports of suspected adverse reactions to a vaccine are the enormous difficulty of distinguishing a causal effect from a coincidence,” he said, adding that the COVID-19 disease was strongly associated with blood clotting.
On Thursday, AstraZenecay told Reuters the safety of its vaccine had been extensively studied in human trials and peer-reviewed data had confirmed the vaccine was generally well tolerated.
The drug maker said earlier this week its shots were subject to strict and rigorous quality controls and that there had been “no confirmed serious adverse events associated with the vaccine”.
It said it was in contact with Austrian authorities and would fully support their investigation.
The European Union’s drug regulator, the European Medicines Agency, said on Wednesday there was no evidence so far linking AstraZeneca to the two cases in Austria.
It said the number of thromboembolic events – marked by the formation of blood clots – in people who have received the AstraZeneca vaccine is no higher than that seen in the general population. There had been 22 cases of such events reported among the three million people who have received it as of March 9.
EMA was not immediately available for comment on Thursday.
Four other countries – Estonia, Lithuania, Luxembourg and Latvia – have also stopped inoculations from the batch while investigations continue, the EMA said.
The batch of one million doses went to 17 EU countries.
Swedish authorities said they did not find sufficient evidence to stop vaccination with AstraZeneca’s vaccine.
Sweden has found two cases of “thromboembolic events” in connection with AstraZeneca’s vaccine and about 10 for the Pfizer-BioNTech vaccine.
“We see no reason to revise our recommendation,” Veronica Arthurson, head of drug safety at the Swedish Medical Products Agency, said.
“There is nothing to indicate that the vaccine causes this type of blood clots.”
On Thursday, Spain said it had registered no cases of blood clots related to AstraZeneca’s vaccine and would continue administering the shots.
Britain’s medicine regulator said people there should keep on getting COVID-19 vaccines, including the shot developed by Oxford and AstraZeneca. The regulator said the Danish suspension was precautionary.