Design
Our study is an observer-blinded, cluster-randomised trial set up among the population of 30 wards in Vellore that are part of the Vellore Health and Demographic Surveillance System (VDSS). Data from the VDSS will be updated with a door-to-door survey and individual residents between the ages of 1 and 30 years will be recruited into the study after informed consent. The wards will be divided into 60 geographically contiguous areas (Fig. Ward map of Vellore city highlighting the trial clusters within the 4 randomisation strataFlow diagram of the study processes