Side effects following vaccination in multiple sclerosis: a prospective, multi-centre cohort study

Abstract

Vaccines play a crucial role in preventing infections in patients with multiple sclerosis (MS), although concerns have been raised about potential worsening of the underlying disease. To investigate this, we conducted a prospective, multicentre, non-randomized observational study assessing changes in disease activity, safety, and clinical tolerability of vaccination in 222 MS patients on disease-modifying drugs. The majority of patients were female (76.6%) and 89.6% had relapsing-remitting MS. The vaccines administered were primarily seasonal influenza (56.3%) or tetanus-based vaccines (33.8%). Disease activity, as measured by annualized relapse rate, decreased significantly from 0.64 the year prior to vaccination to 0.38 in the following year. Moreover, the extended disability status scale remained stable within six months after vaccination in comparison to pre-vaccination values. Side effects were reported in 19.2% of vaccinated subjects, most commonly local side effects (65.2%) or flu-like symptoms (34.8%). Our findings suggest that standard non-live vaccines are safe and well-tolerated in MS patients and do not negatively impact disease activity.

Figure 1

Relapse-free follow-up after vaccination. Graph (Kaplan–Meier plot) shows the probability of relapse-free follow-up after vaccination. Each reduction represents the occurrence of a relapse episode over time in the studied population.

Figure 2

Annualised relapse rate. Mean annualised relapse rates in the study population during 2 years before vaccination and 1 year after vaccination, error bars show standard error of means. Means between year −1 and year +1 are not significantly different, p (year −1 vs. year +1) is > 0.05 (Mann–Whitney U test).

Figure 3

Mean Expanded Disability Status Scale (EDSS) during 24 months before vaccination and 12 months after vaccination. Whisker bars indicate 95% confidence interval. ns not significant.