The Food and Drug Administration on Monday added a warning to the Johnson & Johnson coronavirus vaccine, saying the shot can lead to an increased risk of a rare neurological condition.

Driving the news: Although the chance of developing Guillain–Barré syndrome is "very low," the neurological disorder has occurred in some people who have received the J&J vaccine, the FDA said in its updated fact sheet for recipients of the shot.

• Federal officials have identified around 100 suspected cases of the disease among J&J vaccine recipients based on preliminary reports provided by patients and health care workers.
• Over 12.8 million people have received the J&J COVID vaccine, according to the CDC.
• The reports show that symptoms developed within roughly 42 days of vaccination.

Yes, but: "Although the available evidence suggests an association between the Janssen vaccine and increased risk of GBS, it is insufficient to establish a causal relationship," an FDA official told Axios.

• "Importantly, the FDA has evaluated the available information for the Janssen COVID-19 Vaccine and continues to find the known and potential benefits clearly outweigh the known and potential risks."
• There is no link between the disease and the vaccines developed by Pfizer or Moderna.
• "In the United States, nearly all COVID-19 hospitalizations and deaths are now occurring in unvaccinated people," the Centers for Disease Control and Prevention (CDC) said in a statement on Monday. "The risk of severe adverse events after COVID-19 vaccination remains rare."

The big picture: Johnson & Johnson has faced numerous setbacks in its vaccine deployment, including production delays, ruined doses and a safety pause after blood clots emerged as a side effect.

Worth noting: Around 3,000 to 6,000 people develop Guillain–Barré syndrome every year in the U.S. It's usually triggered by a respiratory or gastrointestinal infection, per the CDC. Most people fully recover.