The primary goal of this study is to provide additional data regarding B and T-cell mediated responses to COVID-19 vaccines in MS patients treated with OCR and to determine which clinical and paraclinical variables correlating with vaccine immunogenicity. B-cell mediated humoral responses and adaptive T-cell mediated cellular responses were measured in patients treated with OCR who received any of the available SARS-CoV-2 vaccines, 3-4 weeks after completion of vaccination.

The purpose of this study is to see if patients on ocrelizumab (Ocrevus) produce a humoral and T-cell response to the coronavirus vaccine. Ocrelizumab depletes B-lymphocytes and has the potential to reduce the effectiveness of vaccines. The impact of ocrelizumab treatment on coronavirus vaccines is unknown.

Natalizumab (Tysabri) likely has a minimal impact the efficacy of vaccines. In this study the investigators will take blood samples in patients being treated with either ocrelizumab or natalizumab before and after vaccination with an FDA-authorized coronavirus (COVID-19) vaccine and compare the antibody response in both groups.

Inclusion Criteria

• Age 18-55
• Diagnosis of multiple sclerosis (as per the revised 2017 criteria)
• EDSS score of 0-5.5 inclusive
• Has initiated ocrelizumab or natalizumab at least 6 months prior to study enrollment
• For women of childbearing potential: agreement to remain abstinent or to use a highly effective (99% efficacy or greater) contraceptive method
• Individual must be able to provide consent, read/write/comprehend English language or must be able to provide a consistent translator

Exclusion Criteria

• Previous infection with COVID-19, confirmed by FDA approved testing
• Cognitive impairment limiting the ability to consent or complete study procedures
• Currently pregnant, planning to become pregnant during the study period, or currently breastfeeding
• Any prior use of immunosuppressive or chemotherapy treatment (including, but not limited to, cladribine, alemtuzumab, mycophenolate mofetil, cyclophosphamide, methotrexate, azathioprine)
• Prior treatment with a B-cell depleting therapy other than ocrelizumab within 12 months of first on-study infusion excluding standard ocrelizumab pre-treatment therapy
• Use of systemic corticosteroid therapy within 12 weeks of screening (excluding corticosteroid treatment given concurrently with ocrelizumab)
• History of allergic reactions to vaccines

Adult Multiple Sclerosis patients receiving treatment with natalizumab or ocrelizumab at the Elliot Lewis MS Center.