multiple sclerosis(14) Patient(12) multiple sclerosis.(12) analysed(11) COVID-19(11) humoral immune response(11) SARS-CoV-2(9) Infection(9) titre(8) B cell(7) patients(7) Immune cell(7) IgG(7) risk(7) T cell response(7) vaccination(7) receiving(7) therapy(7) disorder(6) Infectious diseases(6) clinical neurology(5) cohort of patient(5) collected(5) monitoring(4) multivariate(4) vaccinate(4) antibody(4) anti-N IgG(4) positive serology(4) performed(4)