FDA Strengthens Warning Over Severe Condition Linked to Johnson & Johnson’s COVID-19 Vaccine

A nurse fills a syrgine with Johnson & Johnson's COVID-19 vaccine at a clinic in Pasadena, Calif., in a file photograph. Robyn Beck/AFP via Getty Images

U.S. drug regulators this week formally strengthened a warning to Americans regarding a severe condition linked to Johnson & Johnson’s COVID-19 vaccine.

Blood clots and low blood platelet levels, known as thrombosis with thrombocytopenia syndrome (TTS), are now listed as a contraindication, or a medical reason for somebody not to get the shot.