J&J COVID-19 Vaccine Pause Spotlights Science of Rare Clotting Disorder

The Wall Street Journal reports that researchers are racing to better understand a rare blood-clotting disorder that affected six recipients of Johnson & Johnson's (J&J's) COVID-19 vaccine and led health authorities on Tuesday to suspend its use. Nearly 7 million Americans have received the vaccine. In two studies published in the New England Journal of Medicine , scientists said this immune response appears to target a protein on the surface of platelets. J&J vaccine recipients who experienced the clotting condition were diagnosed with cerebral venous sinus thrombosis, in which clots form inside large blood vessels in the brain with an accompanying drop in platelet levels. The six affected recipients — all women between the ages of 18 and 48 years old — developed symptoms six to 13 days after inoculation, while one male participant in the clinical trial of the J&J vaccine experienced similar clotting. Clots also might be forming in other parts of the body among J&J vaccine recipients, but only ones in the blood vessels in the brain have been spotted thus far partly due to its limited U.S. rollout. Federal officials recommend that people who develop severe headache, abdominal or leg pain, or shortness of breath within three weeks after vaccination should immediately contact their healthcare providers.