The purpose of this study is to collect long-term safety, tolerability, effectiveness and health outcomes data in eligible subjects who have participated in a Novartis ofatumumab clinical MS study. Vaccination sub-study The purpose of this research sub-study is to find out the effects of ofatumumab on the development of antibody responses to selected vaccines and keyhole limpet hemocyanin (KLH) neo-antigen in subjects with relapsing multiple sclerosis (RMS). COVID-19 sub-study: The purpose of this research sub-study is to explore the immune response following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination in a subset of subjects on long-term ofatumumab 20 mg sc. Note: Novartis is not supplying the SARS-CoV-2 vaccine.