9 things to know about Guillain-Barré syndrome and vaccines

The FDA issued a warning July 12 that Johnson & Johnson's COVID-19 vaccine may be associated with a small risk of Guillain-Barré syndrome, a rare neurological disorder, though there's not enough evidence to prove the vaccine causes the condition. 

Nine things to know about Guillain-Barré syndrome and its link to vaccines: 

1. Guillain-Barré syndrome is a rare neurological disorder in which the immune system attacks nerve cells, which can cause muscle weakness and paralysis, according to The New York Times. The cause of the disorder is unknown.
   
   
2. The symptoms of Guillain-Barré syndrome often pass within weeks, but it can sometimes cause permanent nerve damage.
   
   
3. In the U.S., there are about 3,000 to 6,000 cases of Guillain-Barré syndrome each year, according to CDC data cited by the Times. The condition is most commonly seen in men over age 50.
   
   
4. There have been 100 reports of the condition out of the nearly 13 million people who've received Johnson & Johnson's COVID-19 vaccine in the U.S., the Times reported. Of those, 95 cases resulted in hospitalization and one was fatal.
   
   
5. The condition has also been seen in people infected with COVID-19. If the link between the COVID-19 vaccine and Guillain-Barré syndrome is proven, the risks of COVID-19 far outweigh the risk of contracting Guillain-Barré syndrome, experts told the Times.
   
   
6. The COVID-19 vaccine isn't the only vaccine linked to the condition, though the risk of contracting it from any vaccine seems to be very small, according to the Times. A swine flu vaccine campaign in 1976 led to a small increase in the number of Guillain-Barré syndrome cases in the U.S., causing about one extra case of the condition for every 100,000 people vaccinated. The seasonal flu shot is associated with roughly one to two more cases of the condition for every million shots given, and the shingles vaccine Shingrix may increase the risk of the disorder, the Times reported.
   
   
7. Cases of Guillain-Barré syndrome after the COVID-19 vaccine were typically reported about two weeks after vaccination and mostly in men, many of whom were 50 or older, according to the Times. The condition is most likely to appear within 42 days of vaccination, according to the FDA.
   
   
8. There's no data to suggest Guillain-Barré syndrome is linked to Pfizer or Moderna's COVID-19 vaccines, which rely on a different technology than Johnson & Johnson's. The FDA released a statement July 13, saying: "Although the available evidence suggests an association between the Janssen vaccine and increased risk of [Guillain-Barré syndrome], it is insufficient to establish a causal relationship. No similar signal has been identified with the Moderna and Pfizer-BioNTech COVID-19 vaccines."
   
   
9. Experts say people should consult with a physician if they begin to have weakness or tingling in arms or legs; difficulty walking, speaking, chewing, swallowing, or controlling their bladder or bowels after vaccination, as they may be symptoms of Guillain-Barré syndrome.

Read the full Times article here.