Importance The United States Food and Drug Administration conducts routine postmarket 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 & Medicaid Services Medicare Fee-for-Service administrative claims and Medicare Part D data to evaluate risk of Guillain-Barré syndrome following respiratory syncytial virus vaccination. Design, Settings, and Participants We studied vaccines administered between May 3, 2023, when vaccines were first approved, through January 28, 2024. This self-controlled case series study design compared the incidence of Guillain-Barré syndrome during risk intervals of 1 to 42 days following vaccination to the incidence in subsequent control intervals (43 to 90 days) among Medicare beneficiaries, aged 65 years and older, enrolled in Fee-for-Service and Medicare Part D. Exposures Receipt of a single dose of RSVPreF3+AS01 or RSVPreF vaccines. Outcomes Guillain-Barré syndrome was identified using diagnosis code G61.0 in the primary diagnosis position on hospital inpatient claims; returned cases were confirmed via medical record review using the Brighton Collaboration 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 to 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.

The authors have declared no competing interest.

https://bestinitiative.org/wp-content/uploads/2024/01/BEST_RSV_Safety_Older_Adults_2023-2024.pdf

This work was supported by the U.S. Food and Drug Administration through the Department of Health and Human Services (HHS) Contracts [HHSF-223-2018-10020I and GS-10F-0133S], Task Orders [75F40123F19005 and 75FCMC21F0067].

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This surveillance activity was conducted as part of FDA public health surveillance mandate. These safety surveillance activities are not considered research and therefore are exempt from institutional review board review and approval. All individual-level data used in this study was de-identified prior to its use.

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