Inclusion Criteria:  Signed informed consent must be obtained prior to participation in the study Diagnosis of relapsing MS by 2017 revised McDonald criteria Willing to comply with the study schedule Will be receiving an mRNA COVID-19 vaccine (Pfizer or Moderna vaccine) at least two weeks prior to starting ofatumumab Eligible to receive and plan to be started on ofatumumab OR currently on prescribed ofatumumab for ≥ 4 weeks OR currently on commercially prescribed interferon or glatiramer acetate for ≥ 4 weeks  Exclusion Criteria:  Already has received Pfizer, Moderna or Johnson & Johnson vaccine Known diagnosis of COVID-19 prior to screening Has a contraindication to receiving an mRNA COVID-19 vaccine Has an immediate allergic reaction to past vaccine or injection Any major episode of infection requiring hospitalization or treatment with intravenous antibiotics within 2 weeks prior to the screening visit