Table 1

Cluster randomised trials assessing the combination of IRS and LLIN with results available to date

ReferenceCountryTransmission intensityPrimary outcomeIRS productResultComment
Corbel et al 5 BeninModerateIncidence by active case detectionCarbamateNo benefitCarbamate applied every 8 months, not fully covering transmission season
Pinder et al 6 GambiaModerateIncidence by passive case detectionOrganochlorideNo benefitReported LLIN usage >95%
Kafy8 SudanLowIncidence by active case detectionCarbamate or pyrethroidSignificant protection with carbamate
No benefit from deltamethrin
Carbamate IRS in addition to LLINs appeared to slow the emergence of pyrethroid resistance relative to LLINs only.38
West et al 7 TanzaniaHighPrevalenceCarbamateSignificant added protectionEvaluated the incremental effect of two rounds of bendiocarb in Tanzania and found significant added protection, even across a wide range of net usage39
Hamainza et al 40 ZambiaHighRDT positivity rate (community level)Pyrethroid (two different) or organophosphate (two formulations)Significant added benefit (shorter duration for pyrethroids)Found benefit in the combination, even when the insecticide used for IRS was a pyrethroid
  • IRS, indoor residual spraying; LLIN, long-lasting insecticide-treated nets; RDT, rapid diagnostic test.