Tiono, Alfred B, Ouédraogo, Alphonse, Ouattara, Daouda, Bougouma, Edith C, Coulibaly, Sam, Diarra, Amidou, Faragher, Brian, Guelbeogo, Moussa W, Grisales, Nelson, Ouédraogo, Issa N, Ouédraogo, Zininwindé Amidou, Pinder, Margaret
, Sanon, Souleymane, Smith, Tom, Vanobberghen, Fiona, Sagnon, N'Fale, Ranson, Hilary & Lindsay, Steve W.
(2018). Efficacy of Olyset Duo, a bednet containing pyriproxyfen and permethrin, versus a permethrin-only net against clinical malaria in an area with highly pyrethroid-resistant vectors in rural Burkina Faso: a cluster-randomised controlled trial. The Lancet 392
Author(s) from Durham
Background Substantial reductions in malaria incidence in sub-Saharan Africa have been achieved with massive
deployment of long-lasting insecticidal nets (LLINs), but pyrethroid resistance threatens control. Burkina Faso is an
area with intense malaria transmission and highly pyrethroid-resistant vectors. We assessed the effectiveness of
bednets containing permethrin, a pyrethroid, and pyriproxyfen, an insect growth regulator, versus permethrin-only
(standard) LLINs against clinical malaria in children younger than 5 years in Banfora, Burkina Faso.
Methods In this two-group, step-wedge, cluster-randomised, controlled, superiority trial, standard LLINs were
incrementally replaced with LLINs treated with permethrin plus pyriproxyfen (PPF) in 40 rural clusters in Burkina
Faso. In each cluster, 50 children (aged 6 months to 5 years) were followed up by passive case detection for clinical
malaria. Cross-sectional surveys were done at the start and the end of the transmission seasons in 2014 and 2015. We
did monthly collections from indoor light traps to estimate vector densities. Primary endpoints were the incidence of
clinical malaria, measured by passive case detection, and the entomological inoculation rate. Analyses were adjusted
for clustering and for month and health centre. This trial is registered as ISRCTN21853394.
Findings 1980 children were enrolled in the cohort in 2014 and 2157 in 2015. At the end of the study, more than
99% of children slept under a bednet. The incidence of clinical malaria was 2·0 episodes per child-year in the standard
LLIN group and 1·5 episodes per child-year in the PPF-treated LLIN group (incidence rate ratio 0·88 [95% CI
0·77–0·99; p=0·04]). The entomological inoculation rate was 85 (95% CI 63–108) infective bites per transmission
season in the standard LLIN group versus 42 (32–52) infective bites per transmission season in the PPF-treated LLIN
group (rate ratio 0·49, 95% CI 0·32–0·66; p<0·0001).
Interpretation PPF-treated LLINs provide greater protection against clinical malaria than do standard LLINs and
could be used as an alternative to standard LLINs in areas with intense transmission of Plasmodium falciparum
malaria and highly pyrethroid-resistant vectors.
Funding EU Seventh Framework Programme.