Several countries pause use of AstraZeneca COVID-19 vaccine due to blood clot concerns—US still sitting on millions of doses

Multiple countries—including Denmark, Norway, Iceland and Thailand—have temporarily paused the use of the Oxford-AstraZeneca COVID-19 vaccine due to concerns that it might be associated with a high risk of blood clots. The AstraZeneca vaccine is not yet being used in the United States as federal health officials continue to review the data.

Concerns around the world

In Denmark, the Danish Health Authority said it made the decision after learning of numerous reports of blood clots, including one that resulted in death. The group emphasized that it is “by no means discarding the AstraZeneca vaccine”—it just wants more time to study the ongoing situation.

"We are engaged in the largest and most important vaccination rollout in Danish history,” Søren Brostrøm, director general of the Danish Health Authority, said in a statement. “And right now, we need all the vaccine doses we can get. It is, therefore, not an easy decision to pause vaccination with one of the vaccines. However, because we vaccinate so many people, we also need to react with due diligence when we learn of possible and severe side effects.”

The World Health Organization (WHO) responded to these concerns Friday, March 12, telling the media that the AstraZeneca vaccine is “excellent” and should still be used.

The European Medicines Agency, a group that has evaluated and supervised the safety of medicines in the European Union for more than 25 years, has also said that countries should continue using the vaccine.

“The number of thromboembolic events in vaccinated people is no higher than the number seen in the general population,” the group wrote in a statement.

AstraZeneca also commented on this development, saying its own analysis found “no evidence of an increased risk” of blood clots.

Also: In Italy, the Italian Medicines Agency has banned the use of a specific batch of the AstraZeneca vaccine due to “serious adverse events”—but it is unclear at this time if those events were related to blood clots or another complication altogether.

Caution in the United States

The United States is currently in possession of the Oxford-AstraZeneca COVID-19 vaccine—millions of doses, in fact, according to a new report from the New York Times—but it is not yet being used to vaccinate Americans.

While the U.S. government continues to review data, AstraZeneca reached out and asked if some of the country's unused doses could go to other places where there is a greater need. That request, it seems, has been denied.

“We understand other governments may have reached out to the U.S. government about donation of AstraZeneca doses, and we’ve asked the U.S. government to give thoughtful consideration to these requests,” Gonzalo Viña, a spokesman for AstraZeneca, said, as quoted in the New York Times.

Michael Walter
Michael Walter, Managing Editor

Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.

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