Study to Investigate the Immune Response to Influenza Vaccine in Patients With Multiple Sclerosis on Teriflunomide

Inclusion Criteria: \- Male or female patient \<60 years old with relapsing multiple sclerosis (RMS) either treated for at least 6 months with 7 or 14 mg teriflunomide in one of the studies LTS6048 or LTS6050, or treated with a stable dose of interferon-β-1 for at least 6 months. Exclusion Criteria: * Concomitant infectious pathology at the time of vaccination; * MS relapse within 1 month before vaccination; * Systemic corticosteroids within 1 month before the vaccination; * Any contraindication to influenza vaccine; * Any vaccination within the last 6 months; * Prior use of any investigational drug or participation to a clinical trial within 1 year (only for patients under interferon-β-1); * Prior or concomitant use (for a minimum of 1 year before study entry) of cladribine, mitoxantrone, or other immunosuppressant agents such as azathioprine, cyclophosphamide, cyclosporin, methotrexate, mycophenolate, natalizumab (Tysabri®), leflunomide or fingolimod or other immunomodulator/immunosuppressant in development; * Prior or concomitant use of glatiramer acetate within 1 year before study entry; * Prior or concomitant use of intravenous immunoglobulins within 3 months before study entry; * Pregnant or breast feeding women; * Woman of childbearing potential without adequate contraception. The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.