This is a three cohort, multicenter, open-label, prospective study of 60 (optionally up to 90) multiple sclerosis (MS) patients currently treated with siponimod or a first-line disease modifying therapy (DMT) or without MS treatment in clinical routine planning to undergo a SARS-CoV-2 modRNA vaccination as part of clinical routine. The maximal duration of the study for an individual patient is 14 months.~The first cohort in this study will be participants not interrupting their current siponimod therapy for the purpose of a SARS-CoV-2 modRNA vaccination.~The second cohort will be participants interrupting their current siponimod therapy for the purpose of a SARS-CoV-2 modRNA vaccination for approximately 2-3 months.~The third cohort will be participants receiving modRNA vaccine while on treatment with the following first-line DMTs (dimethylfumarate, glatirameracetate, interferons, teriflunomide) or no current treatment in clinical routine.~The study will investigate the development of functional anti-SARS-CoV-2 antibodies and T-cell titers for six months after the participants' vaccination.
The purpose of this study is to understand whether participants can mount an immune response to SARS-CoV-2 modRNA vaccines administered either during continuous siponimod treatment or during a treatment break.