Does RSV Vaccination Cause Guillain-Barré Syndrome

During today's U.S. CDC's Advisory Committee on Immunization Practices (ACIP), Michael Melgar, M.D. presented a summary focused on a small number of Guillain-Barré syndrome (GBS) cases observed in clinical trials within 42 days after U.S. FDA-approved protein subunit RSV vaccinations (GSK Arexvy, Pfizer Abrysvo).

The ACIP Work Group concluded on October 24, 2024, that 'available data support the existence of an increased risk of GBS after protein subunit RSV vaccination. GBS risk following RSV vaccination is rare, with less than 10 cases per 1 million vaccinations.'

However, Moderna’s newly approved mResvia mRNA vaccine has not been associated with an increased risk of GBS. Post-licensure safety surveillance for mResvia began recently in June 2024.

Dr. Melgar's presentation stated, 'Due to the small number of cases (in older adults), it was unclear whether they represented a genuine association between RSV vaccination and GBS.'

The CDC says GBS syndrome happens when a person’s immune system harms their nerves. This harm causes muscle weakness and sometimes paralysis. CDC estimates that only about 3,000–6,000 people develop GBS annually in the United States.