multiple sclerosis(14) Patient(12) multiple sclerosis.(12) COVID-19(11) humoral immune response(11) analysed(11) SARS-CoV-2(9) Infection(9) titre(8) IgG(7) Immune cell(7) risk(7) T cell response(7) vaccination(7) receiving(7) therapy(7) B cell(7) patients(7) disorder(6) Infectious diseases(6) collected(5) cohort of patient(5) clinical neurology(5) Reinfection(4) treatment regimen(4) immune response(4) Linear regression model(4) serological(4) peripheral lymphocyte(4) interferon(4)