multiple sclerosis(14) Patient(12) multiple sclerosis.(12) analysed(11) COVID-19(11) humoral immune response(11) Infection(9) SARS-CoV-2(9) titre(8) patients(7) IgG(7) Immune cell(7) risk(7) T cell response(7) vaccination(7) receiving(7) therapy(7) B cell(7) disorder(6) Infectious diseases(6) collected(5) cohort of patient(5) clinical neurology(5) parameter(4) clinical trial(4) IgA(4) Therapies(4) effective(4) Immunocompromised patient(4) blood sample(4)