Immunogenicity of the Recombinant Zoster Vaccine in Multiple Sclerosis Patients

Inclusion Criteria: For MS patients: * 18 years and above * Diagnosed with relapsing MS according to McDonald Criteria (2017) * Not already vaccinated by RZV and willing to be vaccinated with RZV. * At least 1 year on anti-CD20 treatment: 2 initial infusions of Ocrelizumab 300 mg (2 weeks apart), one infusion of Ocrelizumab 600 mg 6 months apart, one infusion of Ocrelizumab 600 mg 12 months after initial infusions * Informed consent as documented by signature For healthy controls * Aged 50 to 59 * Not already vaccinated by RZV and willing to be vaccinated with RZV * Informed consent as documented by signature Exclusion Criteria: * Recent MS relapse in the 6 weeks preceding planned vaccination * Ongoing signs of febrile or non-febrile infection at the time of vaccination * Recent pregnancy with delivery in the six months preceding vaccination and/or planned pregnancy in the six months following RZV vaccination * Immunosuppression from the following: HIV infection, current active systemic auto-immune disease (other than MS), current malignant neoplasm; primary immunodeficiency; recent solid or bone-marrow transplant or any transplant still requiring immunosuppressive therapy; conditions requiring medication with immunosuppressive drugs * Having received a vaccine in the last month * Having received a shingles vaccine within one year * Presented with herpes zoster in the previous year * Contra-indication to RZV * Unable to provide informed consent or inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia. * Participation in another study with investigational drug within the 30 days preceding and during the present study.