Johnson & Johnson Vaccine on Pause After Six Cases of Rare Blood Clot Reported

Update: Essex County Executive Joseph N. DiVincenzo, Jr. said in a statement Tuesday that “residents who have scheduled a J&J appointment at Kmart or Sears sites will be offered the Moderna vaccine instead. Senior citizens who are being bused to our sites to receive their vaccination also will receive the Moderna vaccine. Unfortunately, our mobile sites at churches, senior buildings, community centers, shelters, boarding homes and homebound residents will be rescheduled.”

More than 6.8 million doses of the Johnson & Johnson (Janssen) vaccine have already been administered in the U.S., but any future doses are on hold indefinitely, as the CDC and FDA, out of an abundance of caution, are recommending a pause in the use of the J&J vaccine. The pause is in response to six reported U.S. cases of a rare and severe type of blood clot in individuals after receiving the J&J vaccine.

In these cases, a type of blood clot called cerebral venous sinus thrombosis (CVST) was seen in combination with low levels of blood platelets (thrombocytopenia). All six cases occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination. 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.

In a joint CDC/DFA medical call Tuesday morning, Dr. Peter Marks, director of the FDA Center for Biologics, Evaluation and Research, said there has been no incidence of CVST in people who have been vaccinated with the Moderna or Pfizer vaccines.

CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance. FDA will review that analysis as it also investigates these cases. The pause is necessary to ensure that the health care provider community is aware of the potential for these rare blood clots and can be prepared for the unique treatment required with this type of blood clot.

“This is an immune response that occurs very, very rarely after some people receive the [J&J vaccine],” said Marks, adding that symptoms occur between one and three weeks after vaccination. He added that practitioners have to be alerted to these rare blood clots as they must be treated differently than other blood clots. He also said this is a recommendation, not a mandate, and that on an individual basis a provider and a patient can make a determination as to whether to receive the vaccine.

New York has already announced it will follow the federal pause on the Johnson & Johnson vaccine.

New Jersey has administered about 220,500 Johnson & Johnson vaccine doses as of Monday afternoon.

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. Health care providers are asked to report adverse events to the Vaccine Adverse Event Reporting System at

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