Health officials are encouraging a nationwide pause on Johnson & Johnson vaccines. 

After 6 women (ages 18-48) developed life-threatening blood clots in response to J&J’s vaccine, doctors are now called to “look in all nooks and crannies” for more patients experiencing similar symptoms. Over 7 million Americans have received the J&J one-dose shot so far. 

Johnson & Johnson’s rollout is also temporarily halted in Europe. Clotting symptoms have been identified between 6-13 days after vaccination, though Peter Marks of the FDA Center for Biologics Evaluation and Research said: 

[The clotting] could just be a statistical aboration. 

Health officials say patients who received J&J’s shot over 1 month ago are at low risk for clotting. Still, officials worry the bad press could fuel existing anxiety around immunizations. 

No definitive cause of the clotting has been identified yet. Here’s Bloomberg with the details.