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Guillain-Barré Syndrome (GBS) Warning Added to RSV Vaccines

The US Food and Drug Administration (FDA) has required safety updates to the prescribing information for the RSV vaccines Abrysvo (by Pfizer) and Arexvy (by GSK). A new warning has been added to inform healthcare providers and patients about a potential increased risk of Guillain-Barré syndrome (GBS) within 42 days after vaccination. GBS is a rare condition where the immune system attacks the nerves, causing muscle weakness and, in some cases, paralysis.

Postmarketing Observational Study Suggesting Increased GBS Risk Following RSV Vaccination

The FDA self-controlled case series GBS update, presented at the October 2024 meeting of the Advisory Committee on Immunization Practices, reported the following conclusions:

  • Our findings suggest an increased GBS risk following RSVPreF3+AS01 [GSK – AREXVY] and RSVPreF [Pfizer – ABRYSVO] among adults aged 65 years and older
  • These results are consistent with pre-licensure clinical trials and surveillance systems such as VAERS
  • End-of-season SCCS analyses results are largely chart-confirmed from MRR and include approximately three times more vaccine doses and GBS cases compared to the early season SCCS results
    • This means that by the end of the RSV season, the analysis had more data available, and the end-of-season analysis included about three times more individuals who received the vaccine and three times more GBS cases, making the findings more robust and reliable compared to the preliminary, early-season results.
  • GBS risk following vaccination with RSVPreF3+AS01 and RSVPreF is rare, with less than 10 cases per 1 million vaccinations
  • There is no difference in GBS risk among persons with and without same day concomitant vaccination with RSV vaccines
    • This finding indicates that receiving an RSV vaccine alongside other vaccines (such as flu or COVID-19 vaccines) on the same day does not increase or decrease the risk of developing GBS compared to receiving the RSV vaccine alone.

ABRYSVO

Abrysvo was initially approved for individuals 60 and older but is now also authorized for younger at-risk adults and pregnant individuals to protect infants from RSV-related illness.

The January 6, 2025, FDA approval letter for ABRYSVO stated the following:

“Since ABRYSVO was approved in 2023, we have become aware of data from a postmarketing observational study conducted among Medicare beneficiaries 65 years of age and older that suggest an increased risk of Guillain-Barré syndrome (GBS) following vaccination with ABRYSVO; please see FDA self-controlled case series GBS update, presented at the October 24, 2024 meeting of the Advisory Committee on Immunization Practices. Therefore, we consider this information to be “new safety information” as defined in section 505-1(b)(3) of the FDCA.

We have determined that an analysis of spontaneous postmarketing adverse events reported under section 505(k)(1) of the FDCA will not be sufficient to assess a serious risk of Guillain-Barré Syndrome following administration of ABRYSVO in pregnant individuals.

Furthermore, the pharmacovigilance system that FDA is required to maintain under section 505(k)(3) of the FDCA is not sufficient to assess this serious risk.

Therefore, based on appropriate scientific data, we have determined that you are required to conduct the following studies: Study titled, “A Rapid Surveillance and Cohort Post-Marketing Safety Study to Evaluate the Safety of Respiratory Syncytial Virus Vaccine (ABRYSVO) Exposure During Pregnancy in the United States” (Protocol C3671027). This postmarketing database study will utilize Sentinel System claims data, including Medicaid claims data, to conduct near real-time monitoring and evaluate Guillain Barré syndrome (GBS) among pregnant women vaccinated with ABRYSVO in the United States.”

AREXVY

Arexvy was initially approved for those 60 and older and is now available for at-risk individuals aged 50-59.

The January 6, 2025, FDA approval letter for AREXVY stated the following:

We have approved your request received on November 22, 2024, to supplement your Biologics License Application (BLA) submitted under section 351(a) of the Public Health Service Act for Respiratory Syncytial Virus Vaccine, Adjuvanted (AREXVY) manufactured at your facility in Wavre, Belgium to update the “Warnings and Precautions” and “Adverse Reactions” sections of the Package Insert to include new safety information on the risk of Guillain-Barré syndrome (GBS) following vaccination
with AREXVY.

The review of this supplement was associated with our October 25, 2024, SAFETY LABELING CHANGE NOTIFICATION LETTER, notifying you, under Section 505(o)(4) of the Federal Food, Drug, and Cosmetic Act (FDCA), of new safety information that we believe should be included in the labeling for AREXVY. This information pertains to data from a postmarketing observational study that suggest an increased risk of GBS during the 42 days following vaccination with AREXVY.

Healthcare providers and patients are encouraged to report any suspected side effects to the Vaccine Adverse Event Reporting System (VAERS).

Citations:

FDA. The FDA Safety Information and Adverse Event Reporting Program. Retrieved from: https://www.fda.gov/safety/medical-product-safety-information/fda-requires-guillain-barre-syndrome-gbs-warning-prescribing-information-rsv-vaccines-abrysvo-and

Meeting of the Advisory Committee on Immunization Practices (ACIP): Respiratory Syncytial Virus (RSV) Vaccine, Adults. October 23-24, 2024. Retrieved from: https://www.cdc.gov/acip/downloads/slides-2024-10-23-24/05-RSV-Adult-Lloyd-508.pdf

Respiratory Syncytial Virus Vaccine Recombinant, Adjuvanted (Arexvy). Vaccines and Related Biological Products Advisory Committee Meeting. FDA Briefing Document. March 1, 2023. https://www.fda.gov/media/165622/download

Respiratory Syncytial Virus Stabilized Bivalent Prefusion F Subunit Vaccine (Abrysvo). Vaccines and Related Biological Products Advisory Committee Meeting. FDA Briefing Document. March 1, 2023. https://www.fda.gov/media/165625/download

Hause AM, 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: http://dx.doi.org/10.15585/mmwr.mm7321a3

Petersen I, Douglas I, Whitaker H. Self controlled case series methods: an alternative to standard epidemiological study designs. 2016;354:i4515.

Evaluation of Multiple Safety Outcomes following Respiratory Syncytial Virus (RSV) Vaccination in Adults 60 Years and Older. BEST Initiative. Center for Biologics Evaluation and Research (CBER). United States Food and Drug Administration (U.S. FDA). https://bestinitiative.org/wp-content/uploads/2024/01/BEST_RSV_Safety_Older_Adults_2023-2024.pdf

Sejvar JJ, Kohl KS, et al, Guillain–Barré syndrome and Fisher syndrome: Case definitions and guidelines for collection, analysis, and presentation of immunization safety data, Vaccine, Volume 29, Issue 3, 2011. https://doi.org/10.1016/j.vaccine.2010.06.003.

Farrington, C. P., et al. (2011). Self-Controlled Case Series Analysis With Event-Dependent Observation Periods. Journal of the American Statistical Association, 106(494), 417–426. https://doi.org/10.1198/jasa.2011.ap10108

Arya, D.P., et al. Surveillance for Guillain-Barré syndrome after 2015-2016 and 2016-2017 influenza vaccination of Medicare beneficiaries. Vaccine, 2019. 37(43): p. 6543-6549.