Published: January 16, 2025
The U.S. Food and Drug Administration (FDA) has issued a warning about a potential increased risk of Guillain-Barré Syndrome (GBS) associated with the administration of RSV vaccines Arexvy (GSK) and Abrysvo (Pfizer). This new advisory highlights the importance of monitoring and educating patients while emphasizing that the benefits of these vaccines outweigh their risks.
What Is Guillain-Barré Syndrome (GBS)?
GBS is a rare neurological disorder where the body’s immune system mistakenly attacks peripheral nerves, leading to muscle weakness and, in severe cases, paralysis. It affects about 3,000–6,000 people annually in the United States, with higher prevalence in men and individuals over 50 years of age.
New FDA Warning
The FDA’s decision stems from data showing a slight increase in GBS cases within 42 days following RSV vaccination. Analysis revealed approximately:
• Nine additional cases of GBS per million doses of Abrysvo.
• Seven additional cases of GBS per million doses of Arexvy.
This data was gathered from clinical trials, postmarketing surveillance, and reports from the U.S. Vaccine Adverse Event Reporting System.
RSV Vaccines Overview
Arexvy and Abrysvo are recombinant vaccines approved to prevent RSV-associated lower respiratory tract disease in adults. Additionally, Abrysvo is indicated for use in pregnant women to protect infants from RSV-related diseases.
• In pivotal trials, isolated cases of GBS and Miller Fisher syndrome were reported shortly after vaccination.
• Moderna’s mResvia (mRNA RSV vaccine) has no reported cases of GBS, and its product monograph does not include a GBS warning.
Health Canada’s Position
While Health Canada has not issued a specific GBS warning, the Canadian Immunization Guide mentions early safety data pointing to a potential increased rate of inflammatory neurologic events, including GBS, after RSV vaccine administration in older adults.
GBS is already listed as a possible adverse effect in the Canadian product monographs for Arexvy and Abrysvo. Canadian health authorities, including the National Advisory Committee on Immunization (NACI), are reviewing the data and may issue updated recommendations.
Weighing Benefits vs. Risks
Despite the small increased risk, the FDA maintains that the benefits of RSV vaccination outweigh the risks, especially for older adults and vulnerable populations at higher risk of severe RSV complications.
Key Takeaways for Healthcare Providers and Patients
1. Monitor Symptoms: Patients vaccinated with Arexvy or Abrysvo should monitor for signs of GBS, such as muscle weakness, difficulty walking, or tingling sensations, and seek medical attention if symptoms occur.
2. Educate Patients: Inform patients about the low but potential risk of GBS and the overall benefits of RSV vaccination.
3. Stay Informed: Follow updates from Health Canada and NACI regarding vaccine recommendations and safety guidelines.
Conclusion
The FDA’s new warning serves as a reminder to balance vaccine benefits against potential risks. RSV vaccination remains a critical tool in preventing severe respiratory illnesses, particularly in high-risk groups. Healthcare providers play a vital role in ensuring patients are informed and protected.
Stay informed, consult trusted sources, and discuss vaccination plans with your healthcare provider.
References:
• FDA and Health Canada Reports
• Clinical Trial Data from GSK and Pfizer
• National Advisory Committee on Immunization (NACI)