FDA temporarily halts use of Johnson & Johnson vaccine due to rare blood clotting issues

Johnson & Johnson COVID-19 vial and box seen at a vaccination site. Doses of the Johnson & Johnson vaccine are being administered throughout the state of Florida despite a small number of patients who have experienced adverse reactions, including blood clots.Paul Hennessy | LightRocket | Getty Images

The Food and Drug Administration said Tuesday it is asking states to temporarily halt using Johnson & Johnson's Covid-19 vaccine after six people in the U.S. developed a rare blood clotting disorder.

The FDA said the recommendation is "out of an abundance of caution," adding the adverse events seen in the handful of recipients appears to be extremely rare.

"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," the FDA said in a joint statement with the Centers for Disease Control and Prevention.

"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," the FDA and CDC said.

The New York Times first reported the news. Shares of J&J were down more than 3% in premarket trading Tuesday.

The CDC will convene a meeting of the Advisory Committee on Immunization Practices on Wednesday to further review the cases, federal health regulators said Tuesday.

When J&J submitted its Covid vaccine data to the FDA in February, no specific concerns were identified when analyzed by age, race and comorbidities, according to the agency. The FDA said at the time the most common side effects reported were headache and fatigue, followed by muscle aches, nausea and fever.

This is breaking news. Please check back for updates.

CNBC