Malnourished children are at increased risk of mortality from infectious diseases such as diarrhea and respiratory tract infections 6. ...the relationship between malnutrition and infection is complex, with undernutrition suppressing the immune system and increasing the risk of infection, and infection causing a reduction in appetite, malabsorption of nutrients, and competition for nutrients 7,8, Provision of antibiotics to malnourished children could lead to clearance of both overt and subclinical infections associated with mortality. Outcomes The outcome for this analysis is mortality, defined as community mortality rate (deaths per 1,000 person-years at risk). Given the fixed design, the prevalence of moderate to severe and severe underweight, and the mortality rates within subgroups, this subgroup analysis had 80% power to detect additive interaction effects of the following sizes, interpreted as the mortality rate among underweight children receiving placebo in excess of the individual effects of underweight or placebo on mortality: 17 deaths per 1,000 person-years for the moderate to severe subgroup and 25 deaths per 1,000 person-years for the severe subgroup 22. Analyses were conducted in R. Participant characteristics, WAZ, and outcomes were summarized by arm using frequency and percentage for categorical variables, mean and standard deviation for continuous variables, and incidence rate (deaths per 1,000 person-years, hereafter referred to as “mortality rate”) and 95% confidence interval for outcomes.