Efficacy of permethrin-treated bed nets in the prevention of mortality in young children in an area of high perennial malaria transmission in western Kenya.
A group-randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) was conducted in an area of high perennial malaria transmission in western Kenya to test the effect of ITNs on all-cause mortality in children 1-59 months of age. Child deaths were monitored over a two-year period by biannual household census in Asembo (1997-1998) and in Gem (1998-1999). Overall, 1,722 deaths occurred in children 1-59 months followed for 35,932 child-years. Crude mortality rates/1,000 child-years were 51.9 versus 43.9 in control and ITN villages in children 1-59 months old. The protective efficacy (PE) (95% confidence interval) adjusted for age, study year, study site, and season was 16% (6-25%). Corresponding figures in 1-11- and 12-59-month-old children in control and ITN villages were 133.3 versus 102.3, PE = 23% (11-34%) and 31.1 versus 28.7, PE = 7% (-6-19%). The numbers of lives saved/1,000 child-years were 8, 31, and 2 for the groups 1-59, 1-11, and 12-59 months old, respectively. Stratified analysis by time to insecticide re-treatment showed that the PE of ITNs re-treated per study protocol (every six months) was 20% (10-29%), overall and 26% (12-37%) and 14% (-1-26%) in 1-11- and 12-59-month-old children, respectively. ITNs prevent approximately one in four infant deaths in areas of intense perennial malaria transmission, but their efficacy is compromised if re-treatment is delayed beyond six months.
Phillips-Howard
Penelope A
PA
Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
Nahlen
Bernard L
BL
Kolczak
Margarette S
MS
Hightower
Allen W
AW
ter Kuile
Feiko O
FO
Alaii
Jane A
JA
Gimnig
John E
JE
Arudo
John
J
Vulule
John M
JM
Odhacha
Amos
A
Kachur
S Patrick
SP
Schoute
Erik
E
Rosen
Daniel H
DH
Sexton
John D
JD
Oloo
Aggrey J
AJ
Hawley
William A
WA
D001512:Bedding and Linens; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005843:Geography; D006801:Humans; D007223:Infant; D007306:Insecticides / Q000494:pharmacology*; D007630:Kenya / Q000453:epidemiology; D008288:Malaria / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D026023:Permethrin / Q000494:pharmacology*; D012621:Seasons
D007306:Insecticides; D026023:Permethrin