Influenza Vaccination Coverage among Multiple Sclerosis Patients: Evolution over Time and Associated Factors

Our objective was to determine the influenza vaccination rate in a Spanish cohort of multiple sclerosis (MS) patients. A retrospective cohort study was carried out. Patients who attended the MS unit of the Lozano Blesa Hospital of Zaragoza between January 2015 and 2020 were included. The variables were obtained by reviewing the specialized and primary care records. Associations between receiving the vaccine in each flu season and the other variables were analyzed using bivariate analysis and multiple logistic regression models. A total of 260 patients were studied, with a median age of 31 years at the time of diagnosis. A total of 62.3% (162/260) were women. Vaccination coverage ranged from 20.4% in the 2015-2016 and 2016-2017 seasons to 41.5% in the 2019-2020 season (p = 0.000). Having been vaccinated in the previous season (ORa: 16.47-390.22; p = 0.000) and receiving a vaccination recommendation from the hospital vaccination unit (ORa: 2.44-3.96; p < 0.009) were associated with being vaccinated. The coverage is in an intermediate position compared to other countries. It is necessary to improve the referral system of these patients to the hospital vaccination unit because the information obtained by this service contributed to higher vaccination rates.