Impact of Disease-Modifying Treatments of Multiple Sclerosis on Anti-SARS-CoV-2 Antibodies: An Observational Study.

OBJECTIVE: To compare the humoral response after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with multiple sclerosis (MS) receiving different disease-modifying treatments (DMTs). METHODS: Patients with MS with coronavirus disease 2019 (COVID-19) and available anti-SARS-CoV-2 serology were included. The primary endpoint was the anti-SARS-CoV-2 immunoglobulin G (IgG) index. The multivariate analysis was adjusted for COVID-19 severity, SARS-CoV-2 PCR result, and the time between COVID-19 onset and the serology. RESULTS: We included 61 patients with available IgG index. The IgG index was lower in patients with fingolimod or anti-CD20 monoclonal antibodies compared with patients without treatment (p < 0.01), patients with interferon s-1a or glatiramer (p < 0.01), and patients with another DMT (p = 0.01). The IgG index was correlated with the time between COVID-19 onset and serology (r = -0.296 [-0.510; -0.0477], p = 0.02). CONCLUSIONS: Humoral response after COVID-19 was lower in patients with MS with fingolimod or anti-CD20 mAb. These patients could therefore be at risk of recurrent infection and could benefit from anti-SARS-CoV-2 vaccination. The humoral response after vaccination and the delay before vaccination need to be evaluated. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that patients treated with fingolimod or anti-CD20 monoclonal antibodies for MS have a lower humoral response after COVID-19 compared with patients without DMTs or with another DMTs.