Denmark will not use AstraZeneca’s COVID-19 vaccine for two weeks after reports that some recipients had developed serious blood clots, and in one case may have died as a result, the country’s authorities said on Thursday.
They did not say how many reports of blood clots there had been, but Austria has stopped using a batch of AstraZeneca shots while investigating a death from coagulation disorders and an illness from a pulmonary embolism.
Danish health authorities said the country’s decision to suspend the shots for 14 days came after a 60-year old woman in Denmark, who was given an AstraZeneca shot from the same batch that was 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.
Norway follows suit
Following Denmark’s move, Norway announced later on Thursday that it was also halting the use of the AstraZeneca vaccine.
“This is a cautionary decision,” Geir Bukholm, director of infection prevention and control at the Norwegian Institute of Public Health (FHI), told a news conference.
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,” Bukholm said.
Also on Thursday, Italy said it would suspend use of an AstraZeneca batch that was different to the one used in Austria.
AstraZeneca meanwhile told Reuters news agency in a written statement 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 drugmaker 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 also said it was in contact with Austrian authorities and would fully support their investigation.
The European Union’s drug regulator, the European Medicines Agency (EMA), 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, with 22 cases of such events being reported among the three million people who have received it as of March 9.
Four other countries – Estonia, Lithuania, Luxembourg and Latvia – have stopped inoculations from the batch while an investigation continues, the EMA said.
The batch of one million doses went to 17 EU countries.
On hold, not opting out, says Denmark
Al Jazeera’s Paul Brennan, reporting from London, said Thursday’s moves by Denmark and Norway appeared to have “been borne of an abundance of caution”.
“The Danish Health Authority has not given any details of exactly how many blood clot cases there have been,” Brennan said.
“But what they did say it was that it was currently not possible to conclude there was a link between the vaccine and these deaths.”
So far, 136,090 Danes have received a shot with AstraZeneca’s vaccine in a country of 5.8 million. The Nordic country also uses vaccines from Pfizer-BioNTech and Moderna.
Denmark’s Health Authority said it had pushed back the final date for when it expects all Danes to have been fully vaccinated by four weeks, to August 15, as a result of the suspension.
Sterghios Moschos, a molecular biologist at the UK’s Northumbria University, said Denmark, Norway and other governments were doing the correct thing to “stop and make sure everything was okay” before proceeding with further use.
“It’s an appropriate response, there is a concern that has been raised, and it needs to be looked at carefully and independently,” Moschos told Al Jazeera.
“But the likelihood, in general, that … a batch of the vaccine may have something wrong with it is very small.”
Spain on Thursday said it had not registered any cases of blood clots related to AstraZeneca’s vaccine so far and would continue administering the shots.
Italy’s medicines authority Aifa confirmed that it was halting the use of a batch of doses as a “precautionary” measure, adding that no link had been established between the vaccine and subsequent “serious adverse events”, Reuters news agency reported on Thursday.
It did not specify what incidents it was referring to.
However, the source said health authorities moved following the deaths this month of Stefano Paterno, a 43-year-old navy officer, and Davide Villa, a 50-year-old policeman, who had both received shots from AstraZeneca’s ABV2856 batch.
Paterno died of a suspected heart attack on Tuesday, the day after his shot. Villa died at the weekend, some 12 days after his inoculation.