The Food and Drug Administration narrowed its use authorization for Johnson & Johnson’s single-dose COVID-19 vaccine due to risks of severe blood clotting, a move that comes months after an initial warning from health officials.

The vaccine, produced by J&J subsidiary Janssen, should only be administered when an mRNA vaccine from Pfizer-BioNTech or Moderna is unavailable due to the risk of severe blood clotting known as thrombosis with thrombocytopenia syndrome, or TTS, the FDA announced Thursday.


“We recognize that the Janssen COVID-19 Vaccine still has a role in the current pandemic response in the United States and across the global community. Our action reflects our updated analysis of the risk of TTS following administration of this vaccine and limits the use of the vaccine to certain individuals,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.

Public health officials have been surveilling cases of the clotting disorder after receipt of the single-dose vaccine since spring 2021, soon after it was granted an emergency use authorization for adults 18 and older. Administration of the shots was placed on pause in April 2021 over concerns about cases of thrombosis in a handful of people.

The pause was lifted later that month. In December, the Centers for Disease Control and Prevention, which makes recommendations for or against FDA authorization, discouraged the use of the vaccine if an mRNA alternative is available. The FDA’s decision Thursday solidified the CDC’s earlier recommendation.

“Today’s action demonstrates the robustness of our safety surveillance systems and our commitment to ensuring that science and data guide our decisions,” Marks said. “We’ve been closely monitoring the Janssen COVID-19 Vaccine and occurrence of TTS following its administration and have used updated information from our safety surveillance systems to revise the EUA.”


Of the three vaccines authorized for public use in the United States, J&J's has been the least frequently used, according to CDC tracking. Nearly 17 million people who are considered fully vaccinated, which does not include booster doses, received the J&J vaccine, compared with 76.5 million who received the Moderna shots and 126.2 million who received the Pfizer-BioNTech vaccine.