Primary outcome
death
The primary outcome of the trial will be 1–14-month-old mortality following the 3-month interval after the village has received the AZI MDA or placebo. We record the vital status of village residents as categorical variable with four options: “alive”, “dead”, “moved”, and “unknown”. In the mortality analysis, the numerator will be binary (alive/dead). For participants whose information on vital status at the end of a 3-month interval, we cannot obtain or infer based on subsequent visits, the interval will be excluded. The denominator, follow-up time, is calculated by subtracting date of first treatment from date of the last vital status or date of death, whichever is earlier. The obtained difference in days is divided by 365.25 to obtain person-years-at-risk (PYR). If the date of death is not obtained for any reason, we will use the mid-point between previous visit and date when death is reported as an approximation.The treatment variable is a three-level categorical variable:Control: category for infants in villages that receive placebo at every visitTwo-dose AZI: category for infants in villages that receive azithromycin two times in a yearFour-dose AZI: category for infants in villages that receive azithromycin at every visit