Denmark bans Johnson & Johnson's coronavirus vaccine, citing the risk of rare blood clots

• Denmark banned Johnson & Johnson's COVID-19 vaccine on Monday.
• Authorities said the risk of unusual blood clots as a side effect outweighed the shot's benefits.
• J&J's vaccine was highly effective in trials, and blood-clot reports have been vanishingly rare.

Denmark has become the first country to stop using Johnson & Johnson's coronavirus shot, weeks after the country banned AstraZeneca's COVID-19 vaccine.

The Danish Health Authority said in a statement Monday that the risk of unusual blood clots outweighed the benefits of the J&J vaccine for the country.

J&J's vaccine was highly effective at preventing COVID-19 in trials but has come under scrutiny across the world following reports of unusual blood clots in six women ages 18 to 48 who received the vaccine in the US. At the time, 6.8 million Americans had received the single-dose vaccine.

The European Medicines Agency said on April 20 that unusual blood clots with low platelets were a rare side effect of J&J's vaccine. But in contrast with Denmark's decision, it determined that the overall benefit of the vaccine outweighed the very low risk of blood clots. European countries can make their own decisions on vaccine rollouts.

The US too halted use of the vaccine in April but immediately resumed its rollout on April 23 after the Food and Drug Administration and the Centers for Disease Control and Prevention said the benefits of the shot outweighed its risks. The ruling followed a 10-day investigation.

The Danish Health Authority said it would continue to monitor the data coming out of the US.

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No Danes have received J&J's vaccine because it was put on hold by the Danish Health Authority while it evaluated it.

The Danish Health Authority noted that other vaccines were available and the COVID-19 outbreak was under control in the country. Denmark has recently reported about 760 new coronavirus cases a day, compared with more than 4,500 in December, according to Johns Hopkins University.

Banning J&J's shot will mean a four-week delay in getting 20- to 39-year-olds immunized, the Danish Health Authority said. The country is using COVID-19 vaccines from Pfizer-BioNTech and Moderna instead, which have had no safety concerns so far.

Denmark stopped using the Oxford-AstraZeneca shot on April 15, following similar concerns about the risk of unusual blood clots. AstraZeneca and J&J's vaccines use a similar technology.

"One should also bear in mind that, going forward, we will first and foremost be vaccinating younger and healthy people," Helene Probst, the deputy director general at the Danish Health Authority, said.

The Danish Health Authority said all 65-year-olds had at least been offered a COVID-19 vaccine. More than 11% of Danes are fully immunized, according to Johns Hopkins University.

Following the EMA's recommendation on J&J's vaccine, France decided to give J&J's shot to over-55s, Italy gave it to over-60s, and Spain to those ages 70 to 79.