Comparing humoral immune response to SARS-CoV2 vaccines in multiple sclerosis and healthy controls: An Austrian multi-center study

Background: Vaccination against SARS-CoV2 is unanimously recommended for patients with multiple sclerosis (MS), although some disease-modifying treatments (DMT) might limit immune response. However, data informing on differences in efficacy and safety of available vaccines in MS patients are scarce. Objective: To compare magnitude and success rate of humoral immune response and safety of SARS-CoV-2 vaccines in patients with MS and healthy individuals. Methods: In this multicenter prospective observational study on 467 MS patients and 124 healthy controls, SARS-CoV-2 IgG response was measured using anti-spike protein-based serology 3 months after the first dose. The primary endpoint was defined as the proportion of patients developing protective antibodies, secondary endpoints included antibody titer, efficacy and safety parameters. Results: Preliminary analyses show that 89.9% of MS patients developed protective levels of anti-SARS-CoV-2 IgG antibodies compared to 97.6% in healthy controls. Positivity rate in patients on immunosuppressive DMT (sphingosine 1 receptor modulators [S1PM], antiCD20 monoclonal antibodies [CD20mAb], cladribine) was significantly lower (63.8%, p<0.001) than in patients without DMT (91.7%) or on immunomodulatory DMT (92.9%;interferon beta, glatiramer acetate, dimethyl fumarate, teriflunomide). Specifically, seroconversion was lowest under CD20mAb (55.2%) followed by S1PM (75%). Detailed analyses reporting antibody titer levels and role of vaccine type, as well as influence of baseline lymphocyte count, time interval from last DMT dosing, vaccine efficacy and safety parameters will be reported at ECTRIMS 2021. Conclusions: Humoral response to SARS-CoV2 vaccines in MS patients is generally excellent. While reduced by immunosuppressive DMT, most importantly by B-cell depleting CD20mAb, protective humoral response is still expected in the majority of patients.