(CNN) The US Food and Drug Administration announced Thursday that it is limiting the emergency use authorization of the Johnson & Johnson/Janssen Covid-19 vaccine to people 18 and older for whom other vaccines aren't appropriate or accessible and those who opt for J&J because they wouldn't otherwise get vaccinated.
The FDA said in a statement that the change is being made because of the risk of a rare and dangerous clotting condition called thrombosis with thrombocytopenia syndrome (TTS) after receiving the vaccine.
"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," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in the statement. "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. ... Today's action demonstrates the robustness of our safety surveillance systems and our commitment to ensuring that science and data guide our actions."
The agency confirmed to CNN that the updated authorization also applies to booster doses.
The FDA says it has determined that the benefits of the J&J vaccine outweigh the risks for certain people. Examples of people who may still get the vaccine include:
As of Thursday, more than 18.7 million doses of the J&J vaccine have been administered in the US, according to the US Centers for Disease Control and Prevention. Of those who are considered fully vaccinated, 7.7% got this vaccine.
After a meeting in December, the CDC's vaccine advisory committee issued an updated recommendation on Johnson & Johnson's vaccine, saying it makes a "preferential recommendation for the use of mRNA COVID-19 vaccines over the Janssen adenoviral-vectored COVID-19 vaccine in all persons aged ≥18 years in the United States."
The committee cited the same concerns over TTS.
Both the CDC and the FDA previously recommended a pause in the use of this vaccine over reports of TTS. The pause was lifted, but that move came with a warning over the rare clotting events.
Johnson & Johnson said in a statement at the time, "The safety and well-being of the people who use our products is our number one priority. We are aware of an extremely rare disorder involving people with blood clots in combination with low platelets in a small number of individuals who have received our COVID-19 vaccine. ... We have been working closely with medical experts and health authorities, and we strongly support the open communication of this information to healthcare professionals and the public."
In an updated fact sheet on the vaccine, the FDA says that 15% of TTS cases have been fatal.
The agency's updated analysis of the vaccine includes cases reported to its Vaccine Adverse Events Reporting System (VAERS) database through March 18. The FDA says it has confirmed 60 cases of TTS, including nine deaths.
Overall, the risk of TTS is extremely rare: about three cases for every million doses of vaccine administered. The highest rate of TTS has been in women 30 to 49 years of age. About eight cases per 1 million doses of vaccine administered have been in women in this age group.
Cases of TTS typically begin one or two weeks after vaccination. Symptoms include shortness of breath, chest pain, leg swelling, persistent abdominal pain, neurological symptoms like headaches or blurred vision, or red spots just under the skin called petechiae beyond the site of vaccination.
The new warning on the vaccine's fact sheet says "The Janssen Covid-19 vaccine can cause thrombosis with thrombocytopenia syndrome (TTS) which may be life-threatening."