Impact of vaccination on COVID-19 outcome in multiple sclerosis

Background and purpose: COVID-19 continues to challenge neurologists in counseling persons with multiple sclerosis (pwMS) regarding disease-modifying treatment (DMT) and vaccination. The objective here was to characterize predictors of COVID-19 outcome in pwMS. Methods: We included pwMS with polymerase chain reaction-confirmed COVID-19 diagnosis from a nationwide population-based registry. COVID-19 outcome was classified as either mild or severe. Impact of DMT, specifically anti-CD20 monoclonal antibodies (anti-CD20), and vaccination on COVID-19 outcome was determined by multivariate models adjusted for a priori risk (determined by a cumulative risk score comprising age, disability, and comorbidities). Results: Of 317 pwMS with COVID-19 (mean age = 41.8 years [SD = 12.4], 72.9% female, median Expanded Disability Status Scale = 1.5 [range = 0-8.5], 77% on DMT [16% on anti-CD20]), 92.7% had a mild course and 7.3% a severe course, with 2.2% dying from COVID-19. Ninety-seven pwMS (30.6%) were fully vaccinated. After a median 5 months from vaccination to SARS-CoV-2 infection (range = 1-9), severe COVID-19 occurred in 2.1% of fully vaccinated pwMS compared to 9.5% in unvaccinated pwMS (p = 0.018). A priori risk robustly predicted COVID-19 severity (R-2 = 0.605, p < 0.001). Adjusting for a priori risk, anti-CD20 treatment was associated with increased COVID-19 severity (odds ratio [OR] = 3.3, R-2 = 0.113, p = 0.003), but exposure to any other DMT was not. Fully vaccinated pwMS showed a significantly decreased risk for severe COVID-19 (OR = 0.21, R-2 = 0.144, p < 0.001). Conclusions: In a population-based MS cohort, COVID-19 course is primarily predicted by a priori risk (depending on age, disability, and comorbidities) explaining about 60% of variance. Anti-CD20 treatment is associated with a moderately increased risk, whereas reassuringly vaccination provides protection from severe COVID-19.

Automated summary

This study analyzed predictors of COVID-19 outcomes in individuals with multiple sclerosis, finding that the severity of the course primarily depends on a priori risk factors. Vaccination significantly reduces the risk of severe COVID-19 in individuals with multiple sclerosis.