Pinder 2015.

Methods	Study design: cRCT with 2 intervention arms Unit of allocation: clusters of villages, each cluster consisted of 1–3 neighbouring villages (97 villages in total) Number of units: 35 randomized clusters in each arm. A subset of 16 clusters per arm was used for entomological assessment Outcome assessment/surveillance type: Children in the study villages aged 6 months to 14 years were sampled according to cluster size and enrolled into a study cohort Incidence rates monitored through passive case detection at local health facilities Prevalence and parasite rates were measured at the end of each transmission season Mosquito density was assessed using light traps and exit traps in 6 sentinel sites in each of 32 clusters, 1 night per month Length of follow‐up: 2 years (2010–2011), 2 transmission seasons (June–December 2010 and 2011) Adjustment for clustering: cluster adjusted measures were presented for some outcomes.
Participants	Number of participants: control: 3949 enrolled children, intervention: 3896 Population characteristics: cohort of children aged < 14 years. Ethnic origin varied with more Mandinka and lower Fula people in the LLIN arm than in the IRS + LLIN arm. Withdrawal and loss to follow‐up: separate analysis was done per survey, each time a survey was done, cohorts would be replenished.
Interventions	Comparison: IRS + ITN versus ITN alone IRS: Active ingredient and dosage: DDT target dose 2 g/m² (2010 mean: 1.69 g/m², 2011: 3.27 g/m²) Formulation: 75% wettable powder Frequency of spraying: once per transmission season (15–28 July 2010, and 20 July to 9 August 2011) Coverage: per cluster in 2010 (%): 86 (range 82.84–90.16); per cluster in 2011 (%): 83 (range 79.27–86.28) Buffer size between clusters: > 2 km ITN: Active ingredient and dosage: permethrin 2% w/w (Olyset Net) Coverage: nets were provided to cover all sleeping spaces as determined by a baseline survey. 59% coverage in June 2010. 89% coverage in January 2011. 93% in January 2012. Compliance: not reported Control: ITN only as above Coverage: 2010: 62%; 2011: 92%; 2012: 96%. Compliance: not reported Cointerventions: none reported
Outcomes	Primary: Incidence of clinical malaria assessed by passive case detection Number of An gambiae s.l. collected per light trap per night Secondary: Haemoglobin concentration Proportion of children with moderate anaemia (< 80 g/L) and severe anaemia (< 50 g/L) Presence of malaria parasites Parasite density Proportion of children with high parasitaemia (> 5000 parasites/μL) Prevalence of children with enlarged spleens measured at the end of the transmission season each year Sporozoite rate estimates in trapped mosquitoes Estimated EIR (mean number of infective mosquito bites per person per season)
Location profile	Study location: Upper River Region of The Gambia, > 110 children aged 6 months to 14 years on 1 June 2010 Malaria endemicity: moderate seasonal malaria transmission EIR: estimated seasonal mean from the control arm of the study measured 2.44 (range 0.69–6.39) in the first year and 0.29 (0.003–2.66) in the second year Population proximity/density: not reported Plasmodiumspp:P falciparum
Vector profile	Primary (and secondary) vector species:An gambiae s.l. Vector behaviour (nature, stability, adult habitat, peak biting times, exophilic/endophilic, exophagic/endophagic, anthropophilic/zoophilic): not reported Phenotypic resistance profile: not reported Genotypic resistance profile: not reported Method of mosquito collection: light and exit traps indoors in 6 rooms in 6 different randomly selected compounds per cluster, 1 night per month
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Villages were randomly assigned using a computerized algorithm.
Allocation concealment (selection bias)	Low risk	Villages were randomly assigned using a computerized algorithm.
Blinding of participants and personnel (performance bias) Incidence of malaria	Low risk	Participants and personnel were not blinded to intervention.
Blinding of participants and personnel (performance bias) Prevalence of malaria	Low risk	For prevalence, risk of bias is low as every participant had their blood taken.
Blinding of outcome assessment (detection bias) Incidence of malaria	Unclear risk	Unclear risk of bias for incidence due to self‐reporting of sickness before confirmation by microscopy, an objective assessment.
Blinding of outcome assessment (detection bias) Prevalence of malaria	Low risk	For prevalence, risk of bias was low as every participant had their blood taken. Observer bias was reduced where feasible. Slide microscopists and their supervisors were blinded to the identity and intervention status of the participants.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Incomplete outcome data were minimal and similar between intervention arms. Attrition between 2010 and 2011 accounted for by topping up cohort with newborn children (312 in LLIN + IRS arm; 324 in LLIN‐only arm).
Selective reporting (reporting bias)	Low risk	The study protocol reported on each outcome as stated in the clinical trials register (note: retrospectively registered).
Recruitment bias	Low risk	Cohort of children were randomly selected.
Baseline imbalance	Low risk	Baseline data were displayed and similar.
Loss of clusters	Low risk	No clusters were lost.
Incorrect analysis	Low risk	Adjustment for clustering was done.
Comparability with RCTs randomizing participants	Low risk	Because the intervention was expected to have community level impact as well as individual impact, cRCTs are the most appropriate study design to capture this.
Other bias	Low risk	No other biases.