Goto 2009

Methods	RCT Length of follow‐up: 36 weeks
Participants	All children living in endemic area Number analysed for primary outcome: 410 Age range: 0 to 11 months Inclusion criteria: infants under 11 months of age in the local area Exclusion criteria: not stated
Interventions	Multiple doses vs placebo Anti‐Giardia (secnidazole every 4 weeks) and anthelminthic (albendazole every 12 weeks); Anti‐Giardia treatment only (secnidazole every 4 weeks) and placebo; Placebo and placebo. Secnidazole: a 70 mg/mL suspension with about 0.5 g of sweetener was made up, and 0.5 mL per kg body weight was given by spoon. If the infant was sick immediately, secnidazole was re‐administrated. Albendazole: a 200 mg (5 mL) suspension given by spoon.
Outcomes	Haemoglobin (g/L) (endpoint week 36). Not included in review: Height‐for‐age z‐score (endpoint week 36); Weight‐for‐age z‐score (endpoint week 36); Weight‐for‐height z‐score (endpoint week 36); Plasma albumin (g/L) (endpoint week 36); IgG (g/L) (endpoint week 36); Alpha‐1‐acid glycoprotein (g/L) (endpoint week 36); Giardia‐specific IgM titre (endpoint week 36); Lactulose/mannitol ratio (endpoint week 36); Prevalence ofGiardia‐specific IgM titre, % (week 0, 12, 24, 36); Prevalence of Giardia cysts, % (week 0, 12, 24, 36); Prevalence of Ascaris/Trichuris, % (week 0, 12, 24, 36); Prevalence of Intestinal mucosal damage, % (week 0, 12, 24, 36); Prevalence of Anaemia,% (week 0, 12, 24, 36).
Notes	Location: Dhamrai Upazila, located 40 km northwest of Dhaka, Bangladesh. Community category: 3. "Prevalences and intensities of geohelminths were consistently low throughout the intervention". Drug source: Dhaka, Bangladesh (Essential Drugs Company Ltd for secnidazole; Square Pharmaceuticals Ltd for the secnidazole placebo; Opsonin Chemical Industries Ltd for albendazole; and UniMed and UniHealthManufacturing Ltd for albendazole placebo).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated. Randomized on the basis of their age, sex, height‐for‐age, weight‐for‐age and weight‐for‐height z‐scores, socio‐demographic and economic data and presence of any parasitic infection.
Allocation concealment (selection bias)	Unclear risk	Unclear whether the allocation was concealed since patients were randomized by their characteristics.
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind. "Bottles containing the two medications and placebo suspensions were labelled with different colours corresponding to the three intervention groups, but the assistants did not know the relationship between the colour codings and the contents of the bottles."
Incomplete outcome data (attrition bias) All outcomes	Low risk	394/410 (96.10%) of randomized participants were evaluated. "A total of 16 infants were excluded from the trial, as they had either moved away from the trial area (n = 12), or were absent during the trial period (n = 2) or the parents subsequently refused to participate (n = 2). Of the infants who completed the trial (n = 394), data on 96 infants was incomplete (ie they did not provide information for all the ten z‐scores and four intestinal permeabilities, serological variables and prevalences of parasite infections), and severe anaemic infants were also omitted from the trial". Inclusion of all randomized participants (number evaluable/number randomized): 96% (394/410).
Selective reporting (reporting bias)	Low risk	All stated outcomes reported.
Other bias	Low risk	No obvious other source of bias.