Description of the sub- study
The cross-sectional data from December surveys was used for risks factors analysis over the three year’ life span of the LLINs. The type of LLIN was considered as the primary exposure therefore the arms receiving the same type of LLIN (Standard LLIN or PBO LLIN) were combined to form two arms regardless of IRS. Sample size was calculated for the first analysis of the RCT and is presented elsewhere [