A Phase IIIB, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Clinical Efficacy Study of Baloxavir Marboxil for the Reduction of Direct Transmission of Influenza From Otherwise Healthy Patients to Household Contacts

Otherwise healthy index patients (IP) are randomized to either baloxavir marboxil or placebo if their influenza symptoms onset was within 48 hours of screening. Their households are enrolled within 24 hours of randomization if at least 1 household contacts (HHC) have not received influenza vaccine within 6 months of screening and if all HHC screen negative for influenza infection. The main endpoints are assessed based on multiple respiratory swabs, obtained from both IP and HHC up to 9 (+/-1) days post IP randomization, and through the assessment of symptoms.