FDA adds Guillain-Barre syndrome warning to J&J Covid shot

FDA has added a warning to Johnson & Johnson's Covid-19 vaccine fact sheet after receiving preliminary reports of patients developing the rare neurological condition Guillain-Barré syndrome after receiving the shot, the agency said Monday.

One hundred suspected cases of GBS — among the 12.8 million people who have gotten the J&J shot — have been identified in the federal government's database for adverse side effects after vaccination, FDA and CDC said. Of those, 95 were serious enough to require hospitalization, and one person died, FDA said.

"Although the available evidence suggests an association between the Janssen vaccine and increased risk of GBS, it is insufficient to establish a causal relationship," FDA said.

While those reports are "rare," a senior CDC official said, they "do likely indicate a small possible risk of this side effect following this vaccine." But the benefits of the J&J shot outweigh the risks of contracting the virus, CDC and FDA said. Nearly all hospitalizations and deaths linked to Covid in the U.S. are occurring among unvaccinated people.

J&J acknowledged in a statement Monday that it's been talking with regulators "about rare cases of the neurological disorder" following vaccination and that the reported case rate "exceeds the background rate by a small degree."

Still, the company touted its vaccine's efficacy in preventing hospitalization and death from Covid-19, even in the face of new variants. "A single-shot vaccine that provides this level of protection represents an important tool in the global fight against COVID-19, as we strive to help end this deadly pandemic," it said.

The Washington Post first reported FDA's plans.

The significance: GBS is a rare condition in which the body's immune system attacks nerve cells. About 3,000 to 6,000 people develop the syndrome every year in the U.S.; most fully recover, though paralysis can occur in the most serious cases.

GBS has been linked as a rare side effect to other vaccines, including a shot developed to fight the 1976 swine flu. Most adverse side effects tied to vaccines are identified within two months of inoculation.

Most of the instances identified in the federal database were reported approximately two weeks after vaccination and were predominantly seen in males ages 50 and older, the senior CDC official said.

"Available data do not show a similar pattern with" the Pfizer and Moderna vaccines, the official said, which are made using a different vaccine technology. Those vaccines have been linked to rare cases of myocarditis, an inflammatory condition of the heart, largely among males younger than 30.

What's next: The CDC's vaccine advisory committee will discuss the issue at an "upcoming" meeting, the official said.

David Lim contributed to this report.