BERLIN — Johnson & Johnson said Tuesday it is delaying the rollout of its coronavirus vaccine in Europe amid a U.S. probe into reports of rare blood clots in some recipients, moves that experts worry could further shake vaccine confidence and complicate COVID-19 immunization efforts.
The announcement came after regulators in the United States said they were recommending a “pause” in the single-dose shot to investigate reports of rare, but potentially dangerous blood clots.
“We have made the decision to proactively delay the rollout of our vaccine in Europe,” Johnson & Johnson said.
The delay is a further blow to vaccination drives in the European Union, which have been plagued by supply shortages, logistical problems and concerns over unusual blood clots in a small number of people who received the AstraZeneca vaccine.
The blood clot reports prompted several countries in the 27-nation bloc to limit the AstraZeneca vaccine to older age groups, which are more at risk from serious illness when infected with COVID-19.
The Johnson & Johnson and AstraZeneca vaccines are made with the same technology. Many leading COVID-19 vaccines train the body to recognize the spike protein that coats the outer surface of the coronavirus. But the J&J and AstraZeneca vaccines use a cold virus, called an adenovirus, to carry the spike gene into the body. Johnson & Johnson uses a human adenovirus to create its vaccine, while AstraZeneca uses a chimpanzee version.
The European Medicines Agency, the EU’s drug regulator, said last Friday that it was reviewing cases reported in the United States of rare blood clots in people who got the J&J vaccine.
In a joint statement Tuesday, the Centers for Disease Control and Prevention and the Food and Drug Administration said they were investigating six cases of unusual clots that occurred six to 13 days after vaccination. The clots occurred in veins that drain blood from the brain and occurred together with low blood platelets.
All six cases were in women between the ages of 18 and 48, including one who died. The FDA commissioner said she expected the pause to last a matter of days.
The Amsterdam-based EMA said following the U.S. announcement Tuesday it is “currently not clear” whether the J&J shot was responsible for the rare clotting disorders.
Last week, the EMA said it found a “possible link” between the AstraZeneca shot and rare blood clots but that it still thought the benefits of vaccination far outweighed the risks of COVID-19. It noted the risk of such clots is less than the blood clot risk that healthy women face from birth control pills.
Dr. Adam Finn, a professor of pediatrics at Britain’s University of Bristol, said it was possible the way the J&J and AstraZeneca vaccines were made may have contributed to the unusual clotting disorders in a very small proportion of people.
“This may help give us a clue towards understanding the mechanism or a way to prevent this problem from occurring,” Finn said in a statement. “Given the importance of these vaccines for the timely control of the pandemic, investigation of this phenomenon is now an extremely urgent international priority.”
The EU ordered 200 million doses of the Johnson & Johnson in 2021. Britain ordered 30 million doses of the J& J vaccine, though U.K. regulators have not yet approved its use.
France had expected to receive 200,000 doses of the vaccine this week and was planning to start administering them next week to people aged 55 and over. In total, the country had planned to receive about 8 million doses of the J&J vaccine by the end of June.
In February, South Africa began vaccinating its health workers with the J&J vaccine in a research trial after abandoning plans to use the AstraZeneca shot when a preliminary study suggested the AstraZeneca vaccine was only minimally effective against the variant of COVID-19 that first arose in the country.
South Africa planned to test the J&J shot in 500,000 health workers as part of the research, and as of Monday night, it had vaccinated 289,787.
Last month, the African Union announced it had signed a deal to buy up to 400 million doses of the J&J vaccine.
Johnson & Johnson also has a preliminary agreement to supply up to 500 million doses to the U.N.-backed COVAX initiative, an effort to provide COVID-19 vaccines to the world’s poor. The World Health Organization last month gave the green light to the J&J vaccine, saying its one-dose formula “should facilitate vaccination logistics in all countries.”
Any concerns about the J&J vaccine could be another unwelcome complication for COVAX and for the billions of people in developing countries depending on the program to get immunized. COVAX recently was hit by supply issues after its biggest supplier, the Serum Institute of India, announced it would delay exports of the AstraZeneca vaccine for several months due to a surge of cases in the subcontinent.
European regulators on March 11 endorsed the Johnson & Johnson vaccine as the fourth authorized for use in the EU, but the first supplies are only now arriving.
Italy expected to receive its first Johnson & Johnson deliveries this week. The Lazio region surrounding Rome planned to give the prison population the single jab, while the northern Veneto region planned to use it for home-bound adults over 80.
Francesco Rocca, president of the International Federation of the Red Cross, told foreign reporters in Italy that the news the vaccine was being “paused” meant the regulatory system was functioning as it should.
“There will be repercussions, as we are waiting for millions of doses. But this means the controls are working,” Rocca said. “If we need to be prudent, we need to be prudent.”
Officials in Germany, which was due to receive 232,800 doses of the vaccine this week and 10.1 million doses by the end of June, said earlier Tuesday that there were no immediate plans to change.
“In principle, we naturally always take such warnings in an international context seriously and investigate them,” Health Ministry spokesman, Hanno Kautz, told reporters in Berlin.
Spain is expecting to receive 300,000 doses of J&J on Wednesday, the first delivery of the jab produced by Johnson & Johnson. Asked about the temporary halt on Johnson & Johnson shots in the United States, Spanish Prime Minister Pedro Sánchez said the benefits of taking the vaccine remain greater than the risks but that he would need to learn more.
“We have to all be aware that all the vaccines being administered to the Spanish population, and the European, as well as American populations, are safe,” Sánchez said.
Cheng reported from London. Mike Corder in The Hague, Colleen Barry in Milan, Aritz Parra in Madrid, Andrew Meldrum in Johannesburg and Sylvie Corbet in Paris contributed to this report.