The CDC and FDA are recommending a “pause” in the use of the Johnson & Johnson COVID-19 vaccine. The health organizations offered the advice “out of an abundance of caution” after learning that an unusual type of blood clot developed in six of the 6.8 million people who received the shot.

“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,” the FDA’s Dr. Peter Marks and the CDC’s Dr. Anne Schuchat said in their joint statement. “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.”

The ongoing investigation will reportedly help to “ensure that the health care 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.”

“Vaccine safety is a top priority for the federal government,” the joint statement continued. “We take all reports of health problems following COVID-19 vaccination very seriously.”

More than a dozen states quickly took heed of the advice. Illinois, Kansas, Georgia, Maryland, Massachusetts, Michigan, Missouri, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Utah, Vermont, Virginia, Washington and Puerto Rico have ceased their distribution of the J&J shot.

The update on the Johnson & Johnson medication was met with criticism from Donald Trump who said that the recommendations made by the CDC and FDA affected the reputation of the successful vaccine.

“The Biden Administration did a terrible disservice to people throughout the world by allowing the FDA and CDC to call a ‘pause’ in the use of the Johnson & Johnson COVID-19 vaccine,” he said in a statement. “The results of this vaccine have been extraordinary, but now it’s reputation will be permanently challenged. The people who have already taken the vaccine will be up in arms, and perhaps all of this was done for politics or perhaps it’s the FDA’s love for Pfizer.”

In an attempt to calm nerves and anxiety related to the news, Jeff Zients, the Biden administration’s COVID-19 response coordinator, ensured that the pause would “not have a significant impact on our vaccination plan” as the Johnson & Johnson shot makes up less than five percent of its overall vaccinations.

Emory University School of Medicine’s Dr. Carlos del Rio later told CNN that a person has a “much higher” chance of getting run over by a car than getting the unusual blood clot after a dose of the vaccine.