vaccines don’t trigger flares in patient with autoimmune disease — German claims study delivers reassurance

Summary This retrospective, population-based cohort study emulated six target trials using German statutory health insurance (BARMER) claims data (2013–2019) to assess whether pneumococcal (PV) or influenza (IV) vaccination increases the risk of emergency hospitalization for disease worsening in patients with multiple sclerosis (MS), inflammatory rheumatic and musculoskeletal disease (iRMD), or inflammatory bowel disease (IBD). Vaccinated patients were 1:1 matched to unvaccinated controls by age and sex, with Cox proportional hazards models adjusting for healthcare-seeking behavior, comorbidity, and immunotherapy exposure over a 90-day risk window. Across 432,768 IMID patients, no increased hospitalization risk was found for either vaccine in any disease group; hazard ratios ranged from 0.60 (iRMD, PV) to 0.94 (MS, IV), with several point estimates suggesting a protective trend, particularly for iRMD following pneumococcal vaccination (HR 0.60, 95% CI 0.38–0.94). Three sensitivity analyses confirmed the robustness of these findings. Comment This large, methodologically rigorous target-trial emulation adds compelling reassurance to a remarkably...