The Food and Drug Administration is attaching a new warning to the Johnson & Johnson COVID-19 vaccine about an increased risk of Guillain-Barr syndrome, a rare neurological disorder.

Regulators said the risk of recipients developing the autoimmune disorder, which affects the nerves, was low, The New York Times reported . And the benefits of getting the vaccine against COVID-19 clearly outweigh the known and potential risks, the FDA said in a statement.

The Centers for Disease Control and Prevention said that about 100 cases of Guillain-Barr had been reported out of nearly 13 million people in the U.S. who got the one-dose Johnson & Johnson vaccine. Cases were primarily reported in men over age 50 and came on about two weeks after vaccination, according to The Washington Post .

Most people fully recover from Guillain-Barr syndrome , according to the CDC.

The Johnson & Johnson shot is still 85% effective at preventing severe disease and 100% effective against hospitalization and death, which are the main goals of COVID-19 vaccination.

The risk of severe adverse events after COVID-19 vaccination remains rare, the CDC said in a statement. Everyone age 12 years and older is recommended to receive a COVID-19 vaccine.

The FDA said it revised its fact sheets for health providers and vaccine recipients of the Johnson & Johnson vaccine to include a warning about GBS.

The Johnson & Johnson vaccine rollout was temporarily paused earlier this year over concerns about extremely rare blood clots among some recipients.

Over 184 million people have gotten at least one dose of a COVID-19 vaccine across the U.S. so far, including the Pfizer and Moderna vaccines, which require two doses.

Coronavirus cases and deaths have plummeted in the U.S. since vaccinations became widely available in the spring, and currently the overwhelming majority of cases are among people who have not been vaccinated.