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.