We will assess childhood mortality over three years, comparing communities where children aged 1-60 months receive biannual oral azithromycin ("Azithromycin" arm) for two years, to communities where the children receive biannual oral placebo ("Control" arm) for two years. During the third year at the Niger site only, everyone will receive azithromycin.
This is a cluster-randomized trial; at each site, communities within a contiguous area of 300,000 to 600,000 individuals will be randomized to azithromycin or placebo using simple random sampling.
Niger contingency study: In the event that mass distributions of oral azithromycin are proven to reduce mortality in 1-60 month-old children, then we will treat all communities in Niger with mass azithromycin distributions to test whether the intervention continues to reduce childhood mortality after the initial 2 years of mass treatments.
