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CDC and FDA pause Johnson & Johnson vaccine over rare blood clot concerns

All six cases occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination.

Susan Morse, Managing Editor

(Photo by Luis Alvarez/Getty Images)(Photo by Luis Alvarez/Getty Images)

The Centers for Disease Control and Prevention and the Food and Drug Administration on Tuesday recommended pausing the Johnson & Johnson vaccine due to concerns of several rare blood clotting cases in individuals who have received the vaccine.

The CDC and the FDA are reviewing data involving six reported U.S. cases of a rare and severe type of blood clot in individuals. This is out of more than 6.8 million doses of the Johnson & Johnson Janssen vaccine that have been administered in the United States as of Monday.

All six cases occurred among women between the ages of 18 and 48, and symptoms occurred six to 13 days after vaccination. 

Right now, these adverse events appear to be extremely rare, according to Dr. Anne Schuchat, principal deputy director of the CDC and Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research. 

CDC said it would convene a meeting of the Advisory Committee on Immunization Practices on Wednesday to further review these cases and assess their potential significance. FDA will review that analysis as it also investigates these cases. 

"Until that process is complete, we are recommending a pause in the use of this vaccine out of an abundance of caution," Schuchat and Marks said by statement. "This is important, in part, to ensure that the healthcare provider community is aware of the potential for these adverse events and can plan for proper recognition and management due to the unique treatment required with this type of blood clot.

"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," they said. 

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 healthcare provider. Healthcare providers are asked to report adverse events to the Vaccine Adverse Event Reporting System at,

The blood clot, called cerebral venous sinus thrombosis, was seen in combination with low levels of blood platelets, or thrombocytopenia. Treatment of this specific type of blood clot is different from the treatment that might typically be administered.

Usually, an anticoagulant drug called heparin is used to treat blood clots. In this setting, administration of heparin may be dangerous, and alternative treatments need to be given, the CDC and FDA said.
Twitter: @SusanJMorse
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