The purpose of this study is to determine the rates of adverse events of interest (AEIs) in a real-world population of participants with relapsing remitting multiple sclerosis (RRMS) receiving Ozanimod, sphingosine-1 phosphate (S1P) receptor modulator, compared to the rates of these events in two population of participants:

• Participants not exposed to ozanimod with RRMS who have received treatment with other S1P-receptor modulators disease modifying treatments (DMTs)
• Participants not exposed to ozanimod with RRMS who have received treatment with other non-S1P-receptor modulators disease modifying treatments (DMTs)

Inclusion Criteria:

• Have a diagnosis of multiple sclerosis (MS) recorded on or before the index prescription
• Have at least 6 months of continuous enrollment in the data source (thereby providing medical and dispensing/prescription history data, along with an operational definition of new use) before the index date

Exclusion Criteria:

• Participants with dispensing/prescription of more than one cohort defining drug on the index date

Other protocol-defined inclusion/exclusion criteria apply

The study population will include men and women at least 18 years old who have a diagnosis of multiple sclerosis and are new users of ("initiate") treatment with one of three cohort-defining treatments. Participants will be grouped into the following cohorts:

• Exposed: Starting ozanimod
• Non-exposed: Starting another sphingosine 1-phosphate (S1P) receptor modulator
• Non-exposed: Starting a disease modifying treatment other than an S1P receptor modulator