April 14 (UPI) -- Denmark became the first country to drop the AstraZeneca COVID-19 vaccine because of a possible link to rare blood clots in vaccinated people.
Danish officials said that 2.4 million doses of the AstraZeneca vaccine would be withdrawn until further notice, the Danish Health Authority said in a statement released Wednesday.
Studies showed a higher than expected frequency of blood clots following doses of the vaccine, the authority said.
On Tuesday, the United States, Canada and the European Union paused use of the Johnson & Johnson vaccine over six cases of blood clots.
The blood clot side effects are considered rare for both AstraZeneca and Johnson & Johnson. The AstraZeneca vaccine is not available in the United States.
In March, Denmark was the first country to postpone use of the AstraZeneca vaccine. That decision was followed by other European countries.
The European Medicines Agency announced last week a possible link with blood clots, but added there was a greater risk of dying from COVID-19.
About 1 million people in Denmark have been vaccinated, with approximately 150,000 of them receiving the AstraZeneca vaccine. People in Denmark can also get the Pfizer/BioNTech and Moderna vaccines.
Danish Health Authority Director General Soren Brostrom said in a statement that the decision was made because Denmark had other vaccines available and the epidemic there was currently under control.
"The upcoming target groups for vaccination are less likely to become severely ill from COVID-19," he said. "We must weigh this against the fact that we now have a known risk of severe adverse effects from vaccination with AstraZeneca, even if the risk in absolute terms is slight," he said.
The authority said it might decide later to start using the vaccine again.
The move was expected to push back Denmark's schedule for vaccination of anyone 16 years old or older to mid-August instead of late July.