The Danish Health Authority on Thursday halted the use of the AstraZeneca coronavirus vaccine for 14 days.
It follows reports of “serious cases of blood clots among vaccinated people,” a statement read.
The Danish Health Authority stopped short of saying there was a direct link between the vaccine and the blood clots, “at the time being.”
Shortly after the announcement, Iceland followed suit.
The Danish Medicines Agency said it had launched an investigation into the vaccine.
The probe is being carried out by corresponding agencies in other EU-countries as well as the European Medicines Agency (EMA).
The EMA is in charge of the evaluation and supervision of medicinal products in the EU.
“Both we and the Danish Medicines Agency have to respond to reports of possible serious side-effects, both from Denmark and other European countries,” the director of the Danish Health Authority, Soren Brostrom, said in a statement.
AstraZeneca said its shots are subject to strict and rigorous quality controls.
It said there have been “no confirmed serious adverse events associated with the vaccine.”
The EMA found no evidence linking the Austrian cases to the AstraZeneca vaccine, the agency said on Wednesday.
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 being reported among the 3 million people who have received the AstraZeneca shot as of March 9.
A delivery of 1 million doses of the shot went to 17 EU countries.
A total of seven European countries have now halted the use of a vaccine batch from AstraZeneca.
Austria stopped using AstraZeneca shots while investigating a death from coagulation disorders and an illness from a pulmonary embolism.
Estonia, Lithuania, Luxembourg and Latvia have also halted inoculations while the investigation continues.
However, Spanish Health Minister Carolina Darias said her country would continue to administer the vaccine and had not discovered any cases of blood clots related to it.
The vaccine developed by the British-Swedish pharmaceutical company has already generated concerns over its efficacy in other countries.
In Germany, many of the vaccine doses developed by the firm are going unused due to worries that it is less effective against virus mutations.
Because of a lack of studies into its effects on older people, the vaccine has been approved in Germany for people younger than 65.
South Africa halted the rollout of the vaccine due to a trial showing it was less effective against the South African B.1.351 COVID variant.