CHICAGO—Scientists at Johnson & Johnson on Friday refuted an assertion in a major medical journal that the design of their COVID-19 vaccine, which is similar AstraZeneca’s, may explain why both have been linked to very rare brain blood clots in some vaccine recipients.
The United States earlier this week paused distribution of the J&J vaccine to investigate six cases of a rare brain blood clot known as cerebral venous sinus thrombosis (CVST), accompanied by a low blood platelet count, in U.S. women under age 50, out of about 7 million people who got the shot.
