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Doctors & Advice, Family Health

J&J Vaccine and Guillain-Barré Syndrome: Information on the FDA Warning


Regulators say the benefits of the vaccine still outweigh any risks.

[Originally published: Jan. 29, 2020. Updated: May 17, 2023]

Note: The Johnson & Johnson (Janssen) COVID-19 vaccine is no longer available in the U.S. In May 2023, existing doses of the J&J vaccine expired and the Centers for Disease Control & Prevention (CDC) directed providers to dispose of any that had gone unused.

Information in this article was accurate at the time of original publication. Because information about COVID-19 changes rapidly, we encourage you to visit the websites of the Centers for Disease Control & Prevention (CDC), World Health Organization (WHO), and your state and local government for the latest information.

Guillain-Barré syndrome (GBS) is a rare neurological disorder in which the immune system attacks the nerves. It can cause muscle weakness and sometimes paralysis. People usually recover from it, but it can lead to hospitalization and, sometimes, permanent damage to nerve cells.

So, it’s not surprising that people have questions upon hearing that about 100 suspected cases of GBS have been identified among 12.8 million people who have received the Johnson & Johnson vaccine. While this figure is low enough to categorize the occurrences as rare, the Food and Drug Administration (FDA) attached a warning (included in fact sheets for patients and providers) in July 2021 to the Johnson & Johnson shot about the increased risk of developing GBS in the 42 days after vaccination.

In December 2021, growing concern over another side effect—a rare number of blood clots in J&J recipients—prompted the Centers for Disease Control (CDC) to endorse a clinical preference for the Pfizer-BioNTech and Moderna shots. But the J&J vaccine is still available; the the FDA and CDC are monitoring the situation and trying to learn more about any relationship between the vaccine and the rare cases of GBS.

What you need to know about the FDA warning

The FDA made its decision based on preliminary reports from vaccine recipients and health care providers, made through the Vaccine Adverse Event Reporting System (VAERS). This is a government reporting system that anyone can use, which collects information and helps identify unusual patterns. Of the 100 reports, 95 were serious and required hospitalization, and there was one reported death. Most of the cases were in men, and many of those men were ages 50 or older. 

The agency made it clear that there is still more learn. “Although the available evidence suggests an association between the Janssen [Johnson & Johnson] vaccine and increased risk of GBS,” the FDA said in a statement, “it is insufficient to establish a causal relationship.” 

What you need to know about Guillain-Barré syndrome

GBS is a disease in which a person’s own immune system mistakenly attacks part of the peripheral nerve system, which includes the nerve network outside of the spinal cord and brain. GBS affects an estimated 3,000 to 6,000 people a year in the U.S.

The disease can range from mild to severe, with symptoms from brief weakness to paralysis, and some people die of it. But most recover, even including the most severe cases. According to the CDC, in about two-thirds of cases, people report having had diarrhea or a respiratory illness several weeks before developing symptoms of GBS. Campylobacter jejuni infection, which causes diarrhea, is one of the most common risk factors, but people also have been diagnosed with GBS after other infections, including influenza, Epstein Barr, Zika virus, and COVID-19.

This is also not the first time people have developed GBS after getting a vaccine, according to data from the CDC. There have been reports of people getting ill from GBS days or weeks after being vaccinated with Shingrix, the shingles vaccine, and after getting the flu shot. In 1976, there was a small increased risk of GBS after swine flu vaccination, which was formulated specifically for a potential pandemic strain of flu virus. (Years later, based on a scientific review of the issue in 2003, the National Academy of Medicine found that people who had received the 1976 swine flu vaccine were at increased risk for GBS.) 

But, as with the Johnson & Johnson COVID-19 vaccine, the risk in all of these vaccine-related situations has been small. And there have been no similar reports of GBS in people who have had the Pfizer or Moderna mRNA two-dose vaccines, which use a different technology than Johnson & Johnson’s vaccine.

Should you still get the Johnson & Johnson vaccine?

The Johnson & Johnson single-shot strategy has been considered especially important in efforts to vaccinate people in areas that have been difficult to reach, especially as the highly contagious Delta variant spreads throughout the U.S. But this is the second warning the FDA has issued for the vaccine. This spring, the agency paused the vaccine “out of an abundance of caution” over an uncommon, but potentially serious, blood clotting disorder that occurred in a small number of recipients; a warning label was applied in April. 

Albert Shaw, MD, PhD, a Yale Medicine infectious diseases specialist, notes that the incidence of GBS after the Johnson & Johnson vaccine, as with other reported associations of GBS with other vaccines, has been very rare. Consequently, “It should not prevent people from receiving the vaccine, as the benefits of the vaccine in preventing serious illness or death from COVID-19 greatly outweigh the risks,” he says.

Plus, warnings to address rare side effects are not unusual. In June, the FDA added a warning to the Pfizer and Moderna vaccines after reports of a small number of cases of myocarditis, an inflammation of the heart muscle, in some young adults and teens who had been vaccinated. That same month, The American Neurological Association reported that two studies had found 11 cases of GBS in people recently vaccinated with the AstraZeneca vaccine. 

What if you think you have symptoms of Guillain-Barré syndrome?

GBS usually starts with sensations of weakness or tingling in both legs, which sometimes spread to the upper body. This feeling can increase until some muscles can’t be used at all—in the most severe cases, the syndrome can lead to paralysis.

While the chance of developing GBS after a Johnson & Johnson vaccination is considered low, the FDA recommends seeking medical attention right away if you notice any of the following symptoms after getting the vaccine:

  • Weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other parts of the body
  • Difficulty walking
  • Difficulty with facial movements, including speaking, chewing, or swallowing
  • Double vision or inability to move eyes
  • Difficulty with bladder control or bowel function

Most people recover from GBS, although this can take anywhere from a few weeks to years for some people. There is no cure, but there are therapies that can lessen the severity and speed recovery. One is called plasma exchange, which involves taking blood, extracting the liquid part (called plasma), and then returning it to the body, which seems to decrease both the duration and severity of the illness.  Another treatment is high-dose immunoglobulin therapy, which is an antibody treatment given intravenously.

If you have been recently vaccinated and think you have symptoms of GBS—or any unusual or severe symptoms at all—tell your vaccination provider or your doctor right away, and make a report to VAERS or call their toll-free number at 1-800-822-7967. If you experience severe reactions, call 9-1-1 or go to the nearest hospital.

[Visit Yale Medicine's Vaccine Content Center for more stories on COVID-19 vaccines.]

Note: Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.