Europe Investigates Reports of Blood Clots in Recipients of J&J's Covid-19 Vaccine

By Eric Sylvers and Jenny Strasburg

The European Union's health agency is investigating a small number of reports of very rare cases of severe blood clots among people who have received the Johnson & Johnson Covid-19 vaccine.

There have been four reported cases of serious blood clots, including one death, in people who received the J&J vaccine, the European Medicines Agency said on Friday. One case occurred in a clinical trial and three were in people given the shot as part of the U.S. vaccination campaign.

The EMA said it isn't clear yet whether there is a connection between the vaccine and the blood clots and that the agency could decide to mandate an update to the safety information included with the vaccine. Last month, the EMA approved the J&J vaccine for use in the EU, but the rollout isn't expected to begin until later this month.

The scrutiny follows weeks of investigation into whether the Covid-19 vaccine co-developed by AstraZeneca PLC is linked to rare blood-clotting disorders.

The J&J review could further delay Europe's already sputtering vaccine campaign and add fodder to the antivaccination movement, which is particularly strong in some EU countries, including France. Europe has vaccinated far fewer people than the U.S., and many countries are banking on the single-jab J&J vaccine to help the continent catch up.

About five million people have received the J&J vaccine in the U.S., according to the Centers for Disease Control and Prevention. The U.S. rollout of the vaccine, which is branded as Janssen, a J&J unit, has been speeding up, though a sharp slowdown in deliveries is expected next week. The J&J vaccine, in addition to being administered in a single dose, has the advantage over those developed by Pfizer Inc. and Moderna Inc. of not needing to be stored at super-cold temperatures.

In a large trial of the vaccine, there were slightly more blood clots among vaccine recipients than among those who received a placebo. The U.S. Food and Drug Administration said it couldn't exclude the possibility that the vaccine contributed to the higher number, and plans to monitor for clots as the J&J shot gets deployed in the larger population.

"Our close tracking of side effects has revealed a small number of very rare events following vaccination," J&J said. "At present, no clear causal relationship has been established between these rare events and the Janssen Covid-19 vaccine."

The company's vaccine, like the one developed by AstraZeneca, is made by engineering a harmless type of virus -- such as an adenovirus that can cause the common cold -- to carry a gene from the coronavirus into the cell.

The AstraZeneca vaccine, which hasn't yet been approved for use in the U.S., has run into a thicket of problems in Europe. It is facing scrutiny about potential side effects, even though tens of millions of doses have already been administered across Europe and around the world.

U.K. and European medicines watchdogs this week said there is strong evidence of a link between the vaccine and very rare but serious blood-clotting events but said that for most people, the benefits of the vaccine still far outweigh the small risk of serious side effects

Italy, Spain, Germany, Australia and many other countries have prohibited its use in younger people who have been shown to be more likely to have issues with blood clotting. The U.K. advised that people under 30 receive a different vaccine, citing the potential relative risks of the AstraZeneca vaccine in younger people less susceptible to the most serious effects of Covid.

This week, the University of Oxford, which co-developed the AstraZeneca vaccine, stopped giving the vaccine to children and teenagers taking part in a small-scale U.K. study. The university said that while no safety issues have arisen in the trial, it suspended vaccinations over concerns about the rare clotting that has shown up in adults.

The EMA has said on several occasions that the benefits of the AstraZeneca vaccine outweigh the risks, despite the agency finding a possible link between the vaccine and the rare instances of blood clots. Younger women have been more likely to experience blood-clotting events, though the EMA has said it hasn't established that gender or age are confirmed risk factors.

On Friday, the EMA also said it is investigating five reports of a condition called capillary leak syndrome among millions of people who have received the AstraZeneca vaccine. The rare disorder involves blood leakage from blood vessels into surrounding tissue, causing swelling and potential organ failure, according to health experts.

From the very small number of instances reported, it isn't known whether there is any connection to the vaccine, the EMA said.

"The EMA's review of a safety signal is routine practice and essential to ensuring that regulators have the most up-to-date information on benefits and risks. Currently there is no evidence of a causal relationship with the vaccine. We are supporting the ongoing review," AstraZeneca said in a statement.

Write to Eric Sylvers at [e-mail] and Jenny Strasburg at [e-mail]

(END) Dow Jones Newswires

04-09-21 1441ET