Officials Will Continue to Assess Guillain-Barré Syndrome Risk After RSV Vaccine

Consistent with prelicensure clinical trials, nearly a year of respiratory syncytial virus (RSV) vaccine use in US older adults showed higher-than-expected rates of Guillain-Barré syndrome after RSV vaccination compared with after COVID-19 vaccination, according to an analysis of early safety findings published in Morbidity and Mortality Weekly Report.

“During August 4, 2023–March 30, 2024, at least 10.6 million adults aged ≥60 years received a recommended RSV vaccine,” wrote corresponding author Anne M. Hause, PhD, of the Centers for Disease Control and Prevention (CDC), Atlanta, Georga, and study coauthors. “During May 3, 2023–April 14, 2024, CDC reviewed data reported after RSV vaccination.”

The analysis focused on safety data from the V-safe surveillance system, which allows enrolled participants to fill out surveys about any vaccination reactions online, as well as the Vaccine Adverse Event Reporting System (VAERS), a voluntary reporting system for adverse events for the public, providers, and manufacturers.

Findings from the safety analysis were mostly consistent with trial findings, which identified Guillain-Barré syndrome as a potential concern, according to the study. Reported rates of Guillain-Barré syndrome after RSV vaccination were 5 reports per million doses of Abrysvo and 1.5 reports per million doses of Arexvy.

Using reported rates of Guillain-Barré syndrome after mRNA COVID-19 vaccination as a background estimate, Guillain-Barré syndrome rates after RSV vaccination were more common than expected, researchers reported. Two RSV vaccine recipients diagnosed with Guillain-Barré syndrome died. The most frequently reported nonserious vaccination reactions in VAERS were expected and included pain in extremity, headache, and fatigue. In V-safe, few patients reported seeking medical care.

“CDC and FDA [US Food and Drug Administration] are conducting population-based surveillance to assess risks for Guillain-Barré syndrome and other adverse events,” researchers wrote. “Findings from these studies will help guide development of Advisory Committee on Immunization Practices recommendations.”

The committee currently recommends RSV vaccination, using shared clinical decision-making, for adults aged 60 years and older.

Reference

Hause AM, Moro PL, Baggs J, et al. Early safety findings among persons aged ≥60 years who received a respiratory syncytial virus vaccine — United States, May 3, 2023–April 14, 2024. MMWR Morb Mortal Wkly Rep. 2024;73:489–494. doi:10.15585/mmwr.mm7321a3