Guillain-Barré Syndrome and the Johnson & Johnson Vaccine: What to Know

Johnson & Johnson’s ailing Covid-19 vaccine could be linked to a slightly increased risk of Guillain-Barré syndrome, a rare but potentially serious neurological condition, federal officials said Monday. The Food and Drug Administration added a warning of possible side effects to their datasheets for the vaccine.

The risk seems very small. To date, there have been 100 reports of the syndrome in people who received the Johnson & Johnson vaccine. Nearly 13 million doses of the vaccine have been given in the United States.

Here are answers to some common questions about the syndrome and how it is related to vaccination.

Guillain-Barré is a rare disease in which the body’s immune system attacks nerve cells. Muscle weakness and paralysis can occur. Although symptoms often pass within weeks, in some cases the condition can cause permanent nerve damage. In the United States, there are typically 3,000 to 6,000 cases of the syndrome each year, according to the Centers for Disease Control and Prevention. It’s most common in adults over 50.

The exact cause of the syndrome is unknown, but in many cases the illness follows another illness or infection, such as the flu. It has also been reported in people with Covid-19.

This isn’t the first vaccine to be linked to Guillain-Barré, although the risk seems small. A major swine flu vaccination campaign in 1976 resulted in a small increase in the incidence of the syndrome; the vaccine caused about one additional case of Guillain-Barré for every 100,000 people vaccinated. Seasonal flu vaccination is linked to about one to two additional cases per million vaccines administered.

“I think the data is pretty compelling that the flu vaccine causes Guillain-Barré syndrome, but it’s a very small risk,” said Daniel Salmon, director of the Institute for Vaccine Safety at Johns Hopkins University.

The shingles vaccine Shingrix may also increase your risk of the disease.

It’s not entirely clear why some vaccines can cause Guillain-Barré. “We don’t really understand the biological mechanism,” said Dr. Salmon. “It’s an incredible frustration.”


July 12, 2021, 5:29 p.m. ET

One hundred reports of the syndrome after vaccination with the Johnson & Johnson shot have been submitted to the federal Vaccine Adverse Event Reporting System (VAERS), officials said Monday. Of these, 95 cases resulted in hospitalization, one of which was fatal.

The syndrome was generally reported about two weeks after vaccination, mostly in men, many of whom were 50 years or older, officials said. There isn’t enough evidence yet to determine that the vaccine is causing the disease, but the FDA will continue to monitor the situation, the agency said in a statement.

There is still no data to suggest a link between the disease and Covid-19 vaccines from Pfizer-BioNTech or Moderna, both of which are based on a different technology, the FDA said.

The syndrome is most likely to occur within 42 days of vaccination, the FDA notes in its revised patient data sheet. You should see a doctor if you experience weakness or tingling in your arms and legs, double vision, or difficulty walking, speaking, chewing, swallowing, or controlling your bladder or bowel.

If the link between the vaccine and Guillain-Barré is real, the risks of Covid-19 seem well outweighed, experts said. In the United States, almost all hospital admissions and deaths from Covid-19 occur in unvaccinated people, the CDC said in a statement. The agency recommends that everyone over the age of 12 get vaccinated.

“Everything carries risks,” said Dr. Salmon. “And the key to making a decision is to optimize the benefits and reduce the risks.” He added, “Covid is a pretty nasty disease that 600,000 people have died from.”

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