Chen‐Hussey 2013.

Methods	Cluster randomized controlled trial (RCT) Unit of randomization was household. Intra‐cluster correlation coefficient (ICC) was not reported. Trial duration: up to 8 months' follow‐up in 2009 and 2010
Participants	Adults or children living in endemic regions of Laos in Attapeu Sekong Provinces. Participants were not screened at start for P. vivax.
Interventions	Topical repellent: 15% DEET and placebo Co‐interventions: LLINs Treatment arms: ‐ Repellent arm: 795 households; 3972 participants; and ‐ Placebo arm: 802 households; 4008 participants.
Outcomes	‐ Participants with malaria parasitaemia confirmed through mRDTs (P. falciparum or P. vivax); ‐ Time to first infection (mean time in person/months to first malaria infection); and ‐ Self‐reported adherence to regular usage of the intervention.
Notes	Conducted in Laos. Trial registration number: NCT00938379 Funded by Population Services International.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Equal group allocation, stratified by village. Heads of households picked treatment codes through lottery system.
Allocation concealment (selection bias)	Low risk	Heads of households picked treatment codes out of a bowl.
Blinding of participants and personnel (performance bias) Parasitaemia	Low risk	The treatment allocation was blinded to both participants and field staff.
Blinding of participants and personnel (performance bias) Time to first infection	Low risk	The treatment allocation was blinded to both participants and field staff.
Blinding of participants and personnel (performance bias) Compliance	Low risk	The treatment allocation was blinded to both participants and field staff.
Blinding of outcome assessment (detection bias) Parasitaemia	Low risk	Assessment of parasitaemia or time to first infection are objective outcomes. “Field staff carrying out randomisation and follow‐up surveys and trial staff performing data entry and analysis were blinded for the length of the trial."
Blinding of outcome assessment (detection bias) Time to first infection	Low risk	Assessment of parasitaemia or time to first infection are not biased because these are objective outcomes.
Blinding of outcome assessment (detection bias) Compliance	Low risk	The treatment allocation was blinded to both participants and field staff.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Similar attrition between 2 groups: 11.7% in intervention and 13.2% in control groups were lost to follow‐up/excluded/withdrew.
Selective reporting (reporting bias)	Low risk	Primary outcome was reported as per protocol. Secondary outcomes included all‐cause fever, but this was not reported; however it is non‐essential information for this study. The data presented on compliance was self‐reported, there was no reporting of compliance measured through "sniff‐checks" although it was described in the Methods section.
Other bias	Low risk	Baseline imbalance Study arms had similar baseline characteristics.