Health authorities are investigating highly unusual blood clots after use of two COVID-19 vaccines, and a rare immune response is the main suspect. The U.S. recommended a pause Tuesday in the use of Johnson & Johnson’s vaccine while they examine six reports of the clots. That’s out of nearly 7 million Americans who have been given the one-dose vaccination. Last week, European authorities said similar clots were possibly linked to the AstraZeneca vaccine. Scientists there first raised the possibility that some people were having an abnormal immune response. An FDA official said that’s the theory as the U.S. now investigates clots in J&J recipients.
