The syndrome was generally reported about two weeks after vaccination, primarily in men, many of whom were 50 or older, officials said. There is not yet enough evidence to establish that the vaccine causes the condition, but the F.D.A. will continue to monitor the situation, the agency noted in a statement.
There is not yet any data to suggest a link between the condition and Covid-19 vaccines made by Pfizer-BioNTech or by Moderna, both of which rely upon a different technology, the F.D.A. said.
What signs and symptoms should I look out for?
The syndrome is most likely to appear within 42 days of vaccination, the F.D.A. notes in its revised fact sheet for patients. You should consult with a doctor if you begin to experience weakness or tingling in your arms and legs, double vision or difficulty walking, speaking, chewing, swallowing or controlling your bladder or bowels.
How is it treated?
The condition is typically treated with either an infusion of antibodies, known as immunoglobulin therapy, or plasma exchange, in which a patient’s blood plasma is removed and replaced.
After the acute phase has passed, many patients receive physical therapy or rehab to rebuild their strength. Most people ultimately make a full recovery, although the process can be slow. Some patients may have long-term fatigue, weakness or pain.
Should I still get a Covid-19 vaccine?
If the link between the vaccine and Guillain-Barré is real, it appears to be far outweighed by the risks of Covid-19, experts said. In the United States, almost all hospitalizations and deaths from Covid-19 are happening in those who are unvaccinated, the C.D.C. said in a statement. The agency recommends that everyone who is 12 or older be vaccinated.
“Everything has risks,” Dr. Salmon said. “And the key to decision-making is to optimize the benefits and reduce the risks.” He added, “Covid is a pretty nasty disease that’s killed 600,000 people.”