For the main study we propose to recruit approximately 6,000 individuals with symptoms of influenza-like illness (ILI) and follow-up an anticipated 1,200 index cases who meet specific criteria (in most cases a positive rapid diagnostic test result, or in some cases those meeting symptom based criteria -further described in 4(d)) and their households. Each household will be randomized to receive one of three interventions, and all household contacts will be followed up. Given an average household size of 3.8, a study of 900 households (from 1,200 randomized households after an anticipated 25% dropout) will involve the enrolment of a total of 3,420 individuals (900 index cases and 2,520 household contacts). Details of the power calculation to justify this sample size are given in 9(c) below.