ObjectiveTo determine whether live-attenuated yellow fever vaccine (YFV) was associated with MS relapse, we evaluated the clinical courses of 23 patients in the year before and the year after immunization at the university hospital of Geneva, Switzerland.MethodsThis self-controlled retrospective cohort included adult patients with MS receiving YFV between 2014 and 2018 and defined the year before vaccination, the 3 months thereafter, and the 9 months following as the pre-exposure (PEP), exposure-risk (ERP), and postrisk (PRP) periods, respectively. The primary outcome was the relative incidence of relapse in the ERP vs the PEP. Secondary end points included the presence of new T2-weighted (T2) or T1-weighted gadolinium-positive (T1Gd+) MRI lesions.ResultsOf 23 patients with MS receiving YFV (20 relapsing MS and 3 primary progressive MS), 17 (74%) were women; mean age was 34 years (SD ±10); and 10 of 23 (40%) were treated with disease-modifying therapies (DMTs). Although 9 patients experienced 12 relapses in the PEP, only one experienced a relapse in the ERP; 3 other patients experienced one relapse each in the PRP. None of the 8 patients receiving natalizumab at the time of vaccination experienced relapse thereafter. In the PEP, ERP, and PRP, 18, 2, and 9 patients had new brain and/or spinal cord lesions on T2 or T1Gd + MRI, respectively.ConclusionsIn this cohort, YF vaccination was associated with neither an increase in MS relapse nor emergence of brain and/or spinal lesions. Further studies are warranted to confirm these findings.Classification of evidenceThis study provides Class IV evidence that for persons with MS, YFV may not increase relapse risk.

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Background and purposeIn 2011, fingolimod was approved in Switzerland for the treatment of relapsing‐remitting multiple sclerosis (RRMS). The aim of the present study was to assess the effectiveness and retention of fingolimod in a real‐life Swiss setting, in which patients can receive fingolimod as both first‐ and second‐line treatment for RRMS.MethodsThis cross‐sectional, observational study with retrospective data collection was performed at 19 sites that comprised both hospitals and office‐based physicians across Switzerland. Sites were asked to document eligible patients in consecutive chronological order to avoid selection bias. Demographic and clinical data from 274 consenting adult patients with RRMS who had received treatment with fingolimod were analyzed.ResultsMean treatment duration with fingolimod was 32 months. Under fingolimod, 77.7% of patients remained free from relapses and 90.3% did not experience disability progression. The proportion of patients who were free from any clinical disease activity, i.e. without relapses and disability progression, was 72.1%. A total of 28.5% of patients had been RRMS treatment‐naïve prior to fingolimod therapy. High long‐term treatment retention rates ranging between 95.7% at 24 months and 87.8% at 36 months were observed.ConclusionIn this Swiss cohort of naïve and pre‐treated subjects with RRMS, the majority of patients under fingolimod treatment showed freedom from relapses and disability progression. In addition, treatment retention rate over 2 and 3 years was high, irrespective of previous treatment.