FDA adds new warning on Johnson & Johnson COVID-19 vaccine

The Food and Drug Administration announced a new warning Monday for the COVID-19 vaccine developed by Johnson & Johnson, saying that the shot has been linked to a serious but rare neurological disorder developed in some who took the vaccine.

The disorder, called Guillain-Barré syndrome, causes a person's immune system to attack the body's nerves. The FDA and the Centers for Disease Control and Prevention announced the warning Monday after 100 preliminary reports of Guillain-Barré were detected in vaccine recipients, according to The Washington Post.

Of the 100 preliminary reports, 95 were serious and required hospitalization, with one report of a death, though neither agency provided further details.

The CDC said reports of the syndrome after the vaccine were rare, "but do likely indicate a small possible risk of this side effect following" taking the Johnson & Johnson vaccine. The FDA added that "the known and potential benefits clearly outweigh the known and potential risks."

People older than 50 are at greater risk of Guillain-Barré syndrome, which usually occurs at a rate of about 60 to 120 cases each week. The causes of the syndrome are unknown, but it is usually developed after infection from a virus, usually influenza. An estimated 3,000 to 6,000 develop the illness each year in the United States.