Clinical effectiveness of coronavirus disease 2019 vaccination in patients with multiple sclerosis stratified by disease-modifying treatment

Background and purposeCoronavirus disease 2019 (COVID-19) vaccination has been associated with a dampened humoral and/or cellular immune response in patients with multiple sclerosis (MS) who were concurrently on disease-modifying treatment (DMT) with B-cell depleting agents or sphingosine-1-phosphate receptor modulators (S1PRMs). Our main goal was to investigate the impact of these DMT classes on the clinical effectiveness of COVID-19 vaccination.MethodsSince March 2020, demographics and clinical data of patients with MS who developed COVID-19 have been collected at the Belgian National MS Centre in Melsbroek. Patients were considered to be 'protected by vaccination' if they were (i) fully vaccinated and (ii) tested positive for COVID-19 in the period ranging from 14 days to 6 months after the last administered vaccine.ResultsOn 19 December 2022, 418 COVID-19 cases were retrospectively identified in 389 individual patients. Hospitalization and mortality rates resulting from the infection were 10.8% and 2.4%, respectively. Being 'unprotected by vaccination' was significantly associated with a worse COVID-19 outcome (i.e., hospitalization and/or death) in the total cohort (N = 418, odds ratio [OR] 3.96), in patients on ongoing DMT other than anti-CD20 agents or S1PRMs (N = 123, OR 31.75) and in patients without DMT (N = 182, OR 5.60), but not in those receiving anti-CD20 agents (N = 91, OR 0.39); the S1PRMs subgroup was considered too small (22 infections) for any meaningful analysis.ConclusionsCoronavirus disease 2019 vaccination protects against severe infection in patients with MS but it was not possible to confirm this effect in those on DMT with B-cell depleting agents. Coronavirus disease 2019 vaccination has been associated with dampened immune responses in patients with multiple sclerosis who are concurrently on B-cell depleting agents or sphingosine-1-phosphate receptor modulators. The results are presented of a Belgian retrospective cohort study comparing COVID-19 outcome between patients with multiple sclerosis that were protected by vaccination and those that were not, across different disease-modifying treatment regimens. Overall, COVID-19 vaccination protected against severe infection but it was not possible to confirm this effect in patients on B-cell depleting agents.image