Open Access Open Badges Research article

Cost-sharing strategies combining targeted public subsidies with private-sector delivery achieve high bednet coverage and reduced malaria transmission in Kilombero Valley, southern Tanzania

GF Killeen123*, A Tami14, J Kihonda1, FO Okumu15, ME Kotas6, H Grundmann17, N Kasigudi1, H Ngonyani1, V Mayagaya1, R Nathan1, S Abdulla, JD Charlwood8, TA Smith2 and C Lengeler2

Author Affiliations

1 Ifakara Health Research and Development Centre, Box 53, Ifakara, Morogoro, United Republic of Tanzania

2 Department of Public Health and Epidemiolology, Swiss Tropical Institute, Socinstrasse 57, Basel, CH 4002, Switzerland

3 School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK

4 KIT (Royal Tropical Institute), Biomedical Research, Meibergdreef 39, 1105 AZ Amsterdam, The Netherlands

5 Faculty of Health Sciences, Moi University, P.O Box 4606, Eldoret, Kenya

6 Department of Biomedical Engineering, Yale University, P.O. Box 208284; New Haven, CT 06520-8284, USA

7 Centre for Infectious Diseases Epidemiology, National Institute for Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven, The Netherlands

8 Danish Bilharziasis Laboratories, Jaegersborg Allé 1-D, Charlottenlund, DK 2920, Denmark

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BMC Infectious Diseases 2007, 7:121  doi:10.1186/1471-2334-7-121

Published: 25 October 2007



Cost-sharing schemes incorporating modest targeted subsidies have promoted insecticide-treated nets (ITNs) for malaria prevention in the Kilombero Valley, southern Tanzania, since 1996. Here we evaluate resulting changes in bednet coverage and malaria transmission.


Bednets were sold through local agents at fixed prices representing a 34% subsidy relative to full delivery cost. A further targeted subsidy of 15% was provided to vulnerable groups through discount vouchers delivered through antenatal clinics and regular immunizations. Continuous entomological surveys (2,376 trap nights) were conducted from October 2001 to September 2003 in 25 randomly-selected population clusters of a demographic surveillance system which monitored net coverage.


Mean net usage of 75% (11,982/16,086) across all age groups was achieved but now-obsolete technologies available at the time resulted in low insecticide treatment rates. Malaria transmission remained intense but was substantially reduced: Compared with an exceptionally high historical mean EIR of 1481, even non-users of nets were protected (EIR [fold reduction] = 349 infectious bites per person per year [×4]), while the average resident (244 [×6]), users of typical nets (210 [×7]) and users of insecticidal nets (105 [×14]) enjoyed increasing benefits.


Despite low net treatment levels, community-level protection was equivalent to the personal protection of an ITN. Greater gains for net users and non-users are predicted if more expensive long-lasting ITN technologies can be similarly promoted with correspondingly augmented subsidies. Cost sharing strategies represent an important option for national programmes lacking adequate financing to fully subsidize comprehensive ITN coverage.