Table 1. Characteristics of included studies and interventions.

Author	Country	Study Design	Study aim	Sample size	Intervention group	Control group	The age range of participant (years)	Loss to follow-up	Type of soil-transmitted helminth species	Outcomes of interest
De Gier et al., 2016	Cambodia	A double-blinded, cluster-randomised, placebo-controlled trial	To study the effects of micronutrient-fortified rice on hookworm infection in Cambodian schoolchildren	1,257	Group 1: UltraRice_original Group 2: UltraRice_improved Group 3: NutriRice All participants received additional school meals including canned fish, vitamin A+D fortified vegetable oil, yellow split peas and iodized salt. All participants received 500mg of mebendazole after baseline data collection	Placebo Rice All participants received additional school meals including canned fish, vitamin A+D fortified vegetable oil, yellow split peas and iodized salt. All participants received 500mg of mebendazole after baseline data collection	7–14	Not reported	Hookworm (no distinction made between the two species)	Improve in STH infection status and cognition for children receiving fortified multi-micronutrients
Al-Mekhlafi et al., 2014	Malaysia	A randomised, double-blinded, placebo-controlled trial	To assess whether vitamin A supplementation can protect children from acquiring or developing STH infections	250	Vitamin A(200,000 IU) supplements followed up by two pieces of fried banana (rich in oil). All participants received a 3-day course of 400 mg/daily albendazole after baseline data collection	Placebo. All participants received a 3-day course of 400 mg/daily albendazole after baseline data collection	7–12	35	Ascaris lumbricoides, Trichuris trichiura, hookworm	Reduction of STH infections in children receiving vitamin A
Ebenezer et al., 2013	Sri Lanka	A prospective, placebo-controlled cluster randomised study	To assess the impact of deworming and iron supplementation on the cognitive abilities of school-age children in Sri Lanka	1,190	Iron supplementation (200mg ferrous sulphate equivalent to 60mg of elemental iron) All participants received 500-mg single-dose mebendazole after baseline testing	Placebo	Reported as school-aged children (age range not reported)	431	Ascaris lumbricoides, Trichuris trichiura, hookworm	Reduction of the prevalence of STH infections and cognition in children receiving deworming and iron supplements
Nchito et al., 2009	Zambia	Randomised, placebo-controlled, double-blind, two-by-two factorial intervention trial	To determine the effect of iron and multi- micronutrients on reinfection with Ascaris lumbricoides	378	Group 1: placebo/ multi-micronutrient group Group 2: Iron/placebo group Group 3: Iron/multi-micronutrient group	Placebo	7–15	163	Ascaris lumbricoides, Trichuris trichiura, hookworm	Reduction in STH reinfections in children receiving iron supplements and multi-micronutrients
Olsen, 2003	Kenya	Randomized, placebo-controlled, double-blind, two-by-two factorial trial	The effect of multimicronutrientsupplementation on reinfection with intestinal helminths and Schistosoma mansoni.	997	multimicronutrient supplementation and multihelminth chemotherapy. All infected participants received a single dose 600mg albendazole after baseline	Placebo. All infected participants received a single dose 600mg albendazole after baseline	8–18	Not reported	Ascaris lumbricoides, Trichuris trichiura, hookworm	Reduction of STH reinfections and reinfection intensity in children receiving multi-micronutrients
Olsen’, Nawiri’ and Friis, 2000	Kenya	Randomised, placebo-controlled double-blind iron supplementation trial	To determine the effects of iron on reinfection rates and intensities of hookworm, Ascaris lumbricoides, Trichuris trichiura, and Schistosoma mansoni	200	Green film-coated ferrous dextran (200 mg corresponding to 60 mg elemental iron). All participants received a 3-day course of 400 mg/daily albendazole after baseline data collection	Placebo. All participants received a 3-day course of 400 mg/daily albendazole after baseline data collection	7–15	30	Ascaris lumbricoides, Trichuris trichiura, hookworm	Reduction of STH reinfections and infection intensities in children receiving iron Supplements