FDA adds rare bleeding risk to J&J shot side effects

The FDA revised the fact sheet for Johnson & Johnson's COVID-19 vaccine Jan. 11 to include new information about the risk of a rare bleeding disorder.

"Reports of adverse events following use of the Janssen COVID-19 vaccine under emergency use authorization suggest an increased risk of immune thrombocytopenia during the 42 days following vaccination," the FDA said in a letter to Janssen Biotech, J&J's biotech arm.