Warning for Guillain-Barré Syndrome Added to the Labels of 2 RSV Vaccines

The prescribing information for the vaccines Abrysvo (respiratory syncytial virus vaccine; Pfizer, New York, NY) and Arexvy (respiratory syncytial virus vaccine, adjuvanted; GSK, London, United Kingdom) has been updated to include new warnings for the risk of Guillain-Barré syndrome (GBS). The Food and Drug Administration (FDA) approved and required the new warnings based on results of a postmarketing observational study that evaluated the risk of GBS following administration of the 2 vaccines. Abrysvo and Arexvy are indicated for the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV).

The following language has been added to the Warnings and Precautions section of each vaccine:

• Abrysvbo: The results of a postmarketing observational study suggest an increased risk of Guillain-Barré syndrome during the 42 days following vaccination with Abrysvo.
• Arexvy: The results of a postmarketing observational study suggest an increased risk of Guillain-Barré syndrome during the 42 days following vaccination with Arexvy.

In the postmarketing observational study, associations between vaccination with Abrysvo and Arexvy and diagnosis with GBS were evaluated in the Medicare claims data from May 2023 to June 2024 for beneficiaries aged ≥65 years. Results of the analysis revealed an increased risk of GBS diagnosis in a 42-day window following vaccination:

• There were approximately 9 excess cases of GBS per million doses of Abrysvo.
• There were approximately 7 excess cases of GBS per million doses of Arexvy.

An FDA Safety Communication about the update to the prescribing information notes that the available evidence from the study is insufficient for establishing a causal relationship between vaccination and GBS diagnosis.