Context Insecticide-treated bednets reduce malaria transmission and child morbidity
and mortality in short-term trials, but this impact may not be sustainable.
Previous investigators have suggested that bednet use might paradoxically
increase mortality in older children through delayed acquisition of immunity
Objectives To determine whether adherence to and public health benefits of insecticide-treated
bednets can be sustained over time and whether bednet use during infancy increases
all-cause mortality rates in older children in an area of intense perennial
Design and Setting A community randomized controlled trial in western Kenya (phase 1: January
1997 to February 2000) followed by continued surveillance of adherence, entomologic
parameters, morbidity indicators, and all-cause mortality (phase 2: April
1999 to February 2002), and extended demographic monitoring (January to December
Participants A total of 130 000 residents of 221 villages in Asembo and Gem
were randomized to receive insecticide-treated bednets at the start of phase
1 (111 villages) or phase 2 (110 villages).
Main Outcome Measures Proportion of children younger than 5 years using insecticide-treated
bednets, mean number of Anopheles mosquitoes per
house, and all-cause mortality rates.
Results Adherence to bednet use in children younger than 5 years increased from
65.9% in phase 1 to 82.5% in phase 2 (P<.001).
After 3 to 4 years of bednet use, the mean number of Anopheles mosquitoes per house in the study area was 77% lower than in a neighboring
area without bednets (risk ratio, 0.23; 95% confidence interval [CI], 0.15-0.35).
All-cause mortality rates in infants aged 1 to 11 months were significantly
reduced in intervention villages during phase 1 (hazard ratio [HR], 0.78;
95% CI, 0.67-0.90); low rates were maintained during phase 2. Mortality rates
did not differ during 2002 (after up to 6 years of bednet use) between children
from former intervention and former control households born during phase 1
(HR, 1.01; 95% CI, 0.86-1.19).
Conclusions The public health benefits of insecticide-treated bednets were sustained
for up to 6 years. There is no evidence that bednet use from birth increases
all-cause mortality in older children in an area of intense perennial transmission