Immunogenicity of the Recombinant Zoster Vaccine in Multiple Sclerosis Patients

Who May Qualify: 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 - willing to sign a consent form as documented by signature For healthy controls - Aged 50 to 59 - Not already vaccinated by RZV and willing to be vaccinated with RZV - willing to sign a consent form as documented by signature Who Should NOT Join This Trial: - 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 weakened immune system; 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 willing to sign a consent form 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. Always talk to your doctor about whether this trial is right for you.