Federal health officials on Tuesday recommended a pause in the administration of Johnson & Johnson’s single-dose COVID-19 vaccine pending a review of six U.S. cases of rare and serious blood clots among more than 6.8 million Americans who received the vaccine.
The blood clot condition is called cerebral venous sinus thrombosis and appeared in the six U.S. cases along with low platelets, which ordinarily help with clotting. All six U.S. cases occurred in women ages 18 to 48 within six to 13 days of getting the vaccine, with one death. According to the CDC and U.S. Food and Drug Administration, the blood clots “appear to be extremely rare.”
It remains unknown whether the blood clots are a side effect of the J&J vaccine or are caused by something else. Unfortunately, the blood clots can’t be treated with the anticoagulant drug heparin, which is the usual treatment for blood clots.
The blood clots prompting a pause in administration of the J&J vaccine in the U.S. appear similar to a rare clotting disorder that European health authorities think is possibly linked to AstraZeneca’s COVID-19 vaccine, which has not yet been authorized in the U.S.
Both the J&J vaccine and the AstraZeneca vaccine use modified versions of adenoviruses.
White House COVID-19 response coordinator Jeff Zients said in a statement the pause in the J&J vaccine won’t significantly impact the U.S. vaccination plan.