General study design. The investigators propose a 1:1:1 individually randomized placebo-controlled trial in which children aged 6-59 months with SAM (based on weight-for-height Z-scores (WHZ) and/or mid-upper arm circumference (MUAC), defined in Eligibility) are randomized to one of three study arms: 1) a single oral 20 mg/kg dose of azithromycin followed by 13 doses of placebo; 2) a 7-day twice-daily course of oral amoxicillin (14 total doses); or 3) 7 days of twice-daily placebo (14 total doses). Children will be followed weekly until nutritional recovery, and then at 8 weeks (primary outcome), and 3, 6, 9, and 12 months to assess relapse and vital status. The primary outcome will be weight gain in g/kg/day at 8 weeks from enrollment. Children in all groups will receive ready-to-use therapeutic food per standard of care guidelines (described below).

Study area and study team. This study will be conducted in Boromo District, Burkina Faso in West Africa. Boromo is in central Burkina Faso and experiences a large burden of SAM annually. As in much of the Sahel, food insecurity and malnutrition are highly seasonal, with the malnutrition season aligning with the rainy season from approximately July through October, prior to the annual harvest in November to December. The central Sahel, which includes Burkina Faso, is a particularly vulnerable region for childhood malnutrition due to seasonal food insecurity, ongoing political instability, and climate change which may alter or shorten growing seasons. The COVID-19 pandemic has increased risk of poor nutritional outcomes among children, particularly in already vulnerable settings. The Sahel, and Burkina Faso in particular, is a critical region for nutritional interventions due to the continued high prevalence of underweight and high mortality rates, and lack of progress in reducing underweight in children. Previous evidence has suggested that the etiology of SAM varies across sub-Saharan Africa, and that SAM in the Sahel may be more likely due to calorie insufficiency (marasmus) compared to other regions that have a higher prevalence of protein malnutrition (kwashiorkor). Amoxicillin has been hypothesized to have greater efficacy in children with kwashiorkor vs marasmus, which may partially explain discrepant results in amoxicillin trials from Malawi and Niger. Given the large burden of malnutrition in the Sahel, evidence tailored specifically to this setting is critical to inform policy. The trial will be conducted jointly by the University of California, San Francisco (PI: Dr. Catherine Oldenburg) and the Centre de Recherche en Santé de Nouna (PI: Dr. Ali Sié). Our team has collaborated on multiple randomized controlled trials for child health since 2016. In addition to expertise in design, conduct, and analysis of antibiotic trials, our team has extensive expertise in pediatric microbiome and resistome outcomes in antibiotic trials (led by Dr. Thuy Doan).

Enrollment facilities. Our pilot study was conducted in 6 health facilities in Boromo over a single malnutrition season. For the full trial, the investigators propose to expand to 18 primary healthcare facilities and enroll over a 3-year period (covering 3 malnutrition seasons). These facilities represent the first tier of the country's government-run healthcare system and provide basic preventative and curative care and are often nurse-led.

Healthcare for children under 5 years of age attending public facilities is free of charge. Primary care facilities typically provide outpatient treatment of common childhood illnesses, vaccination clinics, and antenatal and maternity care. Each facility hosts a nutrition clinic 1-2 days/week during which children are screened and receive care for uncomplicated SAM on an outpatient basis. Children with a clinical complication requiring inpatient treatment will be referred to the local district hospital for treatment and will not be enrolled in the trial. Children in the outpatient nutritional program receive weekly follow-up care, although rates of default outside of trial settings are high. These facilities are typically under-resourced and experience frequent stock-outs of key components of the outpatient SAM treatment package (e.g., RUTF). All enrolled children will receive all components of outpatient SAM package through the trial.

The investigators propose a 1:1:1 randomized double masked placebo-controlled trial to determine whether a single oral dose of azithromycin is superior to 1) amoxicillin or 2) placebo for weight gain in children with SAM. Children aged 6-59 months with SAM per Burkinabé national guidelines will be randomized to one of three study arms and followed for 12 months, with the primary outcome being weight gain (g/kg/day) at 8 weeks after enrollment in the study. Children will be followed weekly until recovery, at 8 weeks, and then every 3 months to assess for relapse and mortality.