Infection incidence and management in multiple sclerosis patients after initiating disease-modifying therapy.

Disease-modifying therapies for multiple sclerosis (MS) are effective, but frequently cost $70,000+/year and can predispose patients to serious infections. This retrospective cohort analysis (N = 3,204) compared rates of infections over a 24-month period by MS medication route of administration and antimicrobial use. Infection rates were: 38.7% (oral), 37.3% (infused), and 36.8% (injectable). Of those infections, antimicrobials were prescribed in 86.5% (oral), 84.3% (infused), and 85.5% (injectable) cases. We found differences within bacterial and herpes zoster infection rates (and antimicrobial use) among new users by medication route of administration. Our findings suggest that pharmacovigilance may inform the shared-decision processes when choosing MS medications.