WASHINGTON D.C. — In a joint statement, the CDC and FDA announced the recommendation of a “pause” on using the single-dose Johnson & Johnson (J&J) COVID-19 vaccine.

The agencies are investigating unusual blood clots in six women that occurred from six to 13 days after being vaccinated.

The clots occurred in veins that drain blood from the brain and occurred together with low platelets. All six cases were in women between the ages of 18 and 48. The reports presented appear similar to a rare, unusual type of clotting disorder that European authorities have possibly linked to the AstraZeneca COVID-19 vaccine.

More than 6.8 million doses of the J&J vaccine have been distributed throughout the U.S., with most cases having mild or no side effects.

While Moderna and Pfizer make up a majority of the vaccines distributed so far, federal distribution sites will pause the use of the J&J vaccine.

FDA Acting Commissioner Janet Woodcock said this is a rare occurrence.

“I’d like to stress these events appear to be extremely rare,” she said. “However, COVID-19 vaccine safety is a top priority.”

A CDC committee will meet April 14 to discuss the cases, while the FDA has launched an investigation into the cause of the clots. The CDC and FDA are recommending people who received the J&J vaccine who are experiencing severe headaches, abdominal pain, leg pain or shortness of breath within three weeks of receiving the vaccine to contact their health care provider.

In a statement, J&J said it is aware of the reports but that no link to the vaccine has been established but is delaying the rollout of the vaccine in Europe.

Health authorities also cautioned against using the blood-thinner heparin, as it may be dangerous. These clotting issues are expected to be treated as if the patient had a heparin reaction by using different kinds of blood thinners and sometimes antibody infusions.

The FDA and CDC are expecting their investigation to be complete within a few days.

Michigan temporarily pauses use of Johnson & Johnson vaccine

Based on recommendations from the FDA and CDC, the Michigan Department of Health and Human Services announced Tuesday that it was asking that all providers in the state temporarily pause the administration of J&J vaccine.

Vaccine providers across the state have been instructed not to administer this vaccine at this time, while the CDC and FDA review further data and assure that clinicians are identifying and reporting any potential adverse reaction. Clinics that are scheduled to administer J&J vaccine will either reschedule or use a different vaccine.

The state is also recommending that people who have received the J&J vaccine and 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: https://vaers.hhs.gov/reportevent.html

“More than 6.8 million doses of the Johnson & Johnson vaccine have been administered in the U.S., and these adverse events appear to be extremely rare,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health. However, out of an abundance of caution, we are following recommendations from FDA and CDC and pausing the use of the Johnson & Johnson vaccine in Michigan.

“As we learn more about this from our federal partners, we will update vaccine providers and Michiganders across the state. We encourage everyone to continue making appointments to be vaccinated with the safe and effective Pfizer and Moderna COVID-19 vaccines at this time. These vaccines are the way we are going to end this pandemic as quickly as possible and move toward a sense of normalcy.”