Evaluation of Guillain-Barré syndrome following Respiratory Syncytial Virus Vaccination among Medicare Beneficiaries 65 Years and Older

Abstract Importance The United States Food and Drug Administration conducts routine post-market surveillance of approved vaccines to identify and characterize health outcomes risk associated with vaccination. Pre-licensure clinical trials of RSVPreF3+AS01 and RSVPreF vaccines identified a small number of Guillain-Barré syndrome cases, a serious acute demyelinating disease, following vaccination. Objective To use Centers for Medicare returned cases were confirmed via medical record review using Brighton Collaboration’s case definition. Results We captured approximately 3.23 million Medicare beneficiaries that received respiratory syncytial virus vaccination during the study period. A total of 95 incident Guillain-Barré syndrome cases were observed following respiratory syncytial virus vaccination. In our chart-confirmed self-controlled case series analysis, we observed an increased incidence of Guillain-Barré syndrome following RSVPreF3+AS01 (IRR: 2.46, 95% CI: 1.19, 5.08) with an attributable risk of 6.5 cases per 1 million doses. We observed an increased, yet not statistically significant, incidence of Guillain-Barré syndrome following RSVPreF (IRR: 2.02, 95% CI: 0.93, 4.40) with an attributable risk of 9 cases per 1 million doses. Conclusion and Relevance Findings from this self-controlled case series study suggest an increased risk of Guillain-Barré syndrome during 1-42 days following respiratory syncytial virus vaccination, with fewer than 10 excess Guillain-Barré syndrome cases per 1 million vaccine doses among Medicare beneficiaries 65 years and older. The U.S. Food and Drug Administration maintains that the substantial benefits of RSV vaccination outweigh these identified risks associated with vaccines. Key Points Question Is there an increased risk of developing Guillain-Barré syndrome (GBS) following vaccination with RSVPreF3+AS01 (AREXVY®) and RSVPreF (ABRYSVO®) among Medicare beneficiaries aged 65 years and older? Findings In a self-controlled case series analysis of Medicare beneficiaries with medical record review, we estimated the incidence rate ratio (IRR) comparing GBS in pre-specified risk and control intervals following vaccination with RSVPreF3+AS01 (IRR: 2.46, 95%CI: 1.19-5.08) or RSVPreF (IRR: 2.02, 95%CI: 0.93-4.40). RSV vaccines were associated with fewer than 10 excess GBS cases per 1 million vaccine doses. Meaning These findings suggest an increased risk of GBS following RSV vaccination.