This study applied a matched cluster, controlled design, using community cluster as the unit of randomization. Communities were first matched during the formative research phase and randomized into treatment (Vita Mamba + deworming) or control (deworming) groups, using a simple experimental 1:1 design. The principal investigator generated the random allocation sequence and assigned the cluster to groups. Children were followed longitudinally for Hb concentration and anthropometric measures were taken at baseline (November 2014) and endline (June 2015). Parents were surveyed at baseline for household-level socioeconomic and demographic information; environmental conditions including water, hygiene, and sanitation; and child diet and morbidities.

All children in the intervention schools received the Vita Mamba once per school day from November 2014 to June 2015, for approximately 26 weeks. Children in both groups received Albendazole at baseline in November 2014. Compliance was monitored by teachers and tracked by collection of empty packages. Lessons learned from another school feeding trial by the study team were applied to increase compliance such as opening the packages for the children immediately prior to consumption to discourage selling or sharing later with family members. Vita Mamba was developed for the urban school trial by the research team with representatives from Edesia (a US-based nonprofit manufacturer of ready-to-use foods with expertise in research and development) and Nutriset (the parent company in the PlumpyField network). Meds & Food for Kids, a nonprofit manufacturer of ready-to-use foods in Haiti using locally produced peanuts, produced the Vita Mamba for this trial. Vita Mamba (50 g) contains 260 kcal and meets >75% of the Recommended Dietary Allowance (RDA) for critical micronutrients (S1 Table).

Inclusion Criteria:

• registration in the study school for 2014-2015 calendar; good health (no fever, congenital health condition, or peanut or soy allergy); and not severely malnourished (weight-for-height [WHZ] <-3)

Exclusion Criteria:

• fever, congenital health condition, or peanut or soy allergy; severely malnourished (weight-for-height [WHZ] <-3)