Feds halt J&J COVID-19 vaccine due to blood clot concern

The FDA and CDC issued a joint statement today recommending the pause in the administration of the Johnson & Johnson COVID-19 vaccine.

As of yesterday, more than 6.8 million doses of the J&J single-dose vaccine had been administered in the U.S. Among recipients of those doses, six cases of a rare and severe type of blood clot have been reported. The CDC and FDA are reviewing data involving these cases.

In such cases, a form of blood clot known as cerebral venous sinus thrombosis (CVST) was seen in combination with low levels of blood platelets (thrombocytopenia), according to the joint statement. All six cases were in women between ages 18 and 48, with symptoms occurring between six and 13 days after vaccination. The New York Times reported that one of the women has died and a second is hospitalized in critical condition.

Treatment for CVST is different from typical blood-clot care, which is an anticoagulant drug called heparin. In these cases, heparin may be dangerous, and alternative treatments are needed, the FDA and CDC said.

The CDC is set to convene a meeting of the Advisory Committee on Immunization Practices (ACIP) tomorrow to review the cases and assess the potential significance, while the FDA plans to review the analysis as part of its own investigation. Until the reviews conclude, the agencies recommended a pause “out of an abundance of caution,” in part to ensure healthcare providers are aware of the potential for these blood clots and can prepare for the proper recognition and management of such events.

“Right now, these adverse events appear to be extremely rare,” the joint statement reads. “COVID-19 vaccine safety is a top priority for the federal government, and we take all reports of health problems following COVID-19 vaccination very seriously. People who have received the J&J vaccine who develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider.”

This is yet another recent stumbling block for the J&J vaccine after a factory error at the Baltimore Emergent BioSolutions facility resulted in 15 million discarded doses of the vaccine last month. Last week, the CDC projected that the company’s COVID-19 vaccine shipments would drop by 86% this week.