This is a single arm, pilot multicenter prospective study in up to 22 participants with relapsing multiple sclerosis. Patients screened for the study can either be scheduled for vaccine, have received a single vaccine with a scheduled second dose, or already completed full course (two dose) vaccination. Fully vaccinated participants must be able to complete immune assay No.1 ≥ 14 days after the second dose of vaccine

Inclusion Criteria:

1. Signed informed consent must be obtained prior to participation in the study
2. Age 18-55 years old inclusive at Screening
3. Diagnosis of relapsing MS by 2017 revised McDonald criteria
4. Must be willing to comply with the study schedule
5. Have received/scheduled vaccination with a FDA approved for emergency use COVID-19 mRNA vaccine (either Pfizer or Moderna) (i) either been scheduled for vaccine, (ii) received a single vaccine with a scheduled second dose, or (iii) already completed full course (two dose) vaccination.
6. Currently receiving ofatumumab for the treatment of RMS (Preoftumumab serology with Hepatitis B testing showing no active or latent infection, as well as serum IgG results to be recorded in the database if available)

Exclusion Criteria:

1. Known clinical diagnosis of COVID-19 prior to screening based on investigator's or patient's personal physician's judgement
2. Has a contraindication to receiving an mRNA COVID-19 vaccine
3. Has an immediate allergic reaction to past vaccine or injection
4. Any safety finding including low IgG and/or low IgM levels requiring an ofatumumab treatment interruption within the 12 weeks immediately prior to vaccination as determined by the HCP
5. Any major episode of infection requiring hospitalization or treatment with intravenous antibiotics within 2 weeks prior to the screening visit
6. Prior treatment with S1P agent within 2 months of study enrollment
7. Prior treatment with natalizumab within 6 months of study enrollment
8. Contraindications to ofatumumab treatment as per the USPI will be adhered to which include active infection hepatitis B infection, progressive multifocal leukoencephalopathy and pregnancy.
9. Participation in another interventional clinical trial within 14 days before enrollment.
10. Have been treated with any of the medications as described in the full protocol
11. Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, unless they are using highly effective methods of contraception while taking study treatment and for 6 months after stopping medication

Relapsing MS participants receiving a full course (two doses) of a COVID-19 mRNA vaccine after starting ofatumumab 20 mg subcutaneous treatment