Estimating Risk of Guillain-Barré Syndrome in US Medicare-enrolled Older Adults Following Medically Attended Respiratory Syncytial Virus Disease: A Self-controlled Case Series Analysis.

backgroundGuillain-Barré syndrome (GBS) is considered a rare complication of viral respiratory infections (eg, influenza, severe acute respiratory syndrome coronavirus 2); however, its association with respiratory syncytial virus (RSV) infection has not been studied. We performed a self-controlled case series analysis to estimate GBS risk following medically attended RSV disease among older adults.

methodsWe identified adults aged ≥65 years with medically attended RSV disease and incident inpatient GBS using specific International Classification of Diseases (ICD) codes, excluding those with prior GBS, from the US Medicare claims data (2011-2024). Risk period was 1 to 42 days after the RSV disease index date; the control period encompassed -180 to -22 days and 43 to 180 days of RSV disease index date. Conditional Poisson regression estimated RSV-related GBS incidence rate ratios (IRRs), adjusting for seasonality and viral activities. Medicare data policies prohibit cell case counts <11 from being displayed.

resultsAmong 452 471 eligible patients with RSV disease, <11 incident GBS cases occurred in the risk period and 34 during the control period. The adjusted IRR for GBS after RSV disease was 2.11 (95% confidence interval, 1.01-4.37), consistent across sensitivity analyses of alternative risk/control periods and after excluding coinfections. The IRR increased to 2.59 (1.17-5.73) after ICD-10 code adoption, with a marked rise among patients aged ≥75 years (3.98 [1.45-10.91]).

conclusionsGBS risk increases after RSV disease compared to control periods not temporally adjacent to RSV disease, with an effect particularly evident among patients aged ≥75 years. RSV should be recognized as 1 of the pathogens that may rarely lead to GBS.