Johnson & Johnson's COVID-19 vaccine wins renewed backing from U.S. experts after probe into rare blood clots

After officials halted Johnson & Johnson’s COVID-19 vaccine rollout in its tracks last week, U.S. vaccine advisers agreed on Friday that vaccinations should resume. Going forward, the shot will carry a warning about rare and severe blood clots, they said.

Of the nearly 8 million doses administered, officials identified 15 cases of thrombosis with thrombocytopenia (TTS), CDC vaccine advisers said Friday. Three vaccine recipients who developed TTS have died. All of those stricken have been women, with 13 of them aged 18-49, the experts said.

Officials from the FDA and CDC recommended the halt on April 13 after noticing 6 cases of severe blood clots in around 7 million recipients of the vaccine. The FDA was expected to make its own announcement on the shot's future on Friday, as well. 

J&J’s warning label will include information about symptoms associated with the rare but serious blood clots. The label will warn about the fatalities and contain info about how to treat TTS. 

“J&J strongly supports this labeling,” Joanne Waldstreicher, the chief medical officer at J&J, said during a CDC working group meeting on Friday afternoon. 

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During the session, the CDC presented data which led to its recommendation to resume distribution of the shot.  

Women in the 18-49 age group had an incidence of seven TTS cases per million doses administered, experts said. Among women age 50 and older, the incidence was about 1 per million doses administered. Of the 4 million doses provided to men, there have been no reports of TTS. 

While resumption of the shot is good news for J&J, there is a significant challenge ahead for the company as it attempts to rebuild public confidence in a vaccine that some consider inferior.  

Another adenovirus vaccine, the one developed by AstraZeneca, has also endured a pause and safety fears in Europe. Last week the European Union announced that it would not renew supply contracts with either company after this year.  

Shortly after the U.S. announced its pause, Johnson & Johnson halted deliveries of the vaccine to Europe. On Tuesday, the European Medicines Agency concluded that a link between the vaccine and TTS cases was possible but that the benefits of the shot outweighed the risks.  

The company has resumed supply of the vaccine to Europe. It has pledged 55 million doses to the European Union by the end of June. 

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Another immediate concern for J&J is its supply chain. Last week, at the urging of the FDA, an Emergent BioSolutions plant in Baltimore temporarily halted production of bulk drug substance. Just two weeks earlier, the FDA had turned COVID-19 vaccine manufacturing at the plant over to J&J.