On Tuesday, the U.S. recommended putting on hold the use of the single-dose Johnson & Johnson COVID-19 vaccine.
The U.S. Centers for Disease Control and Prevention and the Food and Drug Administration (FDA) said in a joint statement they are investigating blood clots in six women in the days after vaccination, in combination with reduced platelet counts.
Canada has approved the vaccine but hasn’t yet received any doses. Here’s what we know about what led the U.S. to make this decision,