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When do insecticide-treated net distribution programs work?

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  • Elie Hassenfeld
    Insecticide-treated net (ITN) distribution programs are among those that have strong independent evidence of effectiveness (see our report at
    Message 1 of 1 , Apr 7, 2009
      Insecticide-treated net (ITN) distribution programs are among those that have strong independent evidence of effectiveness (see our report at http://givewell.net/node/329).

      One unanswered question in that report is: when are programs successful? Do they require marketing and education or is distribution enough? Does distribution through health clinics work or is mass distribution along with vaccination campaigns better?

      I tried to answer these questions by looking at the three examples of large-scale, successful (as measured by reduced mortality) ITN programs in Gambia, Tanzania, and Kenya.

      In brief, there's not much to go on. None of the summary papers details the distribution at a level that allows us to clearly state what factors lead to success (and even if they did, there's no way to know that those factors are either necessary or sufficient for success). Nevertheless, this is what we gleaned:
      • All 3 programs had some degree of education/marketing connected with distribution, so distribution, alone, may not be adequate
      • All 3 programs had relatively high ITN-coverage rates in the target areas, so saturation might matter.
      Relevant quotes from the papers follow. Full citations are on our bednets report page: http://givewell.net/node/329#Sources

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      Kenya

      (From Noor 2007 Pg 1342)

      Phase 1: "In January 2002 the UK Department for International Development (DFID) awarded PSI-Kenya US$33 million over 5 y to socially market partially subsidised ITN within the existing retail sector. The programme, named PSI CoveragePlus, was the only major operational ITN distribution initiative between 2002 and 2004 and aimed to target urban and rural retail outlets with Supanet ITNs across all malariaendemic districts in Kenya. A two-tier pricing system of 350 Kenya Shillings (KES) (equivalent to US$4.7) in urban settings versus KES100 (US$1.3) in rural settings was implemented."

      Phase 2: "In June 2004, DFID approved an additional US$19 million to PSI to establish a parallel distribution system of heavily subsidised ITNs to children and pregnant women through Maternal and Child Health (MCH) clinics, recognizing that these vulnerable groups might not be able to access socially marketed commercial sector nets. The programme began in October 2004, and during the first 6 mo Supanet ITNs were bundled with separate Powertab net treatment tablets (for every 6 mo) and distributed to MCH attendees."

      Phase 3: "The implementation of the free mass distribution of LLINs was arranged in two phases during 2006. During the first phase, 21 of Kenya’s 70 districts were selected for distribution of LLINs from 8 to 12 July 2006 and integrated with the national measles catch-up vaccination campaign. Health facilities and centralised non-health facility posts were identified by the Kenya Expanded Programme on Immunisation and used as delivery points of both measles vaccine and LLINs to each child under the age of 5 y. A second mass distribution of LLINs, not integrated with any other intervention, took place from 25 to 27 September 2006 in 24 additional districts using previous mass vaccine campaign delivery centres as distribution points."

      "By the end of September 2006, the three principal net distribution strategies (retail social marketing, heavily subsidized clinic distribution, and free mass distribution) were all operating in parallel, providing an opportunity to examine socioeconomic targeting of each of the delivery mechanisms (Table 2)." Noor 2007, Pg 1345

      There was also PSI marketing in mass media - http://www.psi.org/resources/pubs/kenya-ITN.pdf, Pgs 1-2

      Bottlenecks: "What we can say is that if funding is not secured for clinic supply and catch-up mass campaigns for LLIN delivery beyond 2008 the impressive, rapid progress toward the RBM target of 80% coverage by 2010 in Kenya will be lost." Noor 2007, Pg 1347

      "The effect of ITNs on mortality when delivered under operational conditions has only been measured in The Gambia, as part of a national campaign,4 and in one district in Tanzania after the promotion of socially marketed ITNs.5,6" Fegan 2007, Pg 1035

      Tanzania

      "In an assessment of the only national programme of net treatment in Africa to date, d’Alessandro and colleagues8 reported from The Gambia that communal net treatment distributed free of charge by regional health teams led to improved child survival. However, people were unwilling to pay for services that had once been free, and mortality rates returned to their previous values after the introduction of a cost-recovery programme." Armstrong 2001, Pg 1241

      "In 1996, we developed a social marketing programme, known as KINET, for insecticide-treated nets in two rural districts of Tanzania (Kilombero and Ulanga), with the aim of achieving substantial and sustainable use of such nets in young children and pregnant women. The positive effect of insecticide-treated nets on malaria and anaemia in children is described elsewhere.12" Armstrong 2001, Pg 1242

      "The social marketing was phased in from May, 1997, to June, 1999, starting in the 25 villages covered by the demographic surveillance system (figure 1) and reaching one or two more divisions every few months (figure 2). Treated nets and insecticide for net treatment were introduced together in each area. After sensitisation meetings in 1996, formative research studied householders’ perceptions of causes of child death, mosquito nets, net treatment, and malaria.18 Details of the social marketing programme are given elsewhere.19 Briefly, treated nets (pretreated with 20 mg/m2 deltamethrin, supplied by Siamdutch, Bangkok, Thailand; A to Z, Arusha, Tanzania; or TMTL, Dar es Salaam, Tanzania) and insecticide for net treatment at home (lambdacyhalothrin, Icon, Zeneca, Haslemere, UK) were packaged and branded according to local preferences. Sales agents in each village included health workers, shopkeepers, religious leaders, and village government members. At first, different agents were chosen for nets and insecticide, but, over time, many agents started selling both products. Successful agents were generally shopkeepers and a few health personnel. Every division had a wholesale agent." Armstrong 2001, Pg 1242

      "A comprehensive information, education, and communication campaign was developed and implemented. Increased emphasis was given to the insecticide when it became clear that insecticide-treated nets were more popular than net treatment. Retail prices were set at around US$5 for a treated net and $0·42 for insecticide treatment kits. Retail prices of nets remained the same throughout the study period. Higher-dose net treatment kits were sold at $0·50 from February, 2000. In 1997, ex-factory prices were subsidised by about 25% for nets and 90% for treatment kits. By 2000, ex-factory prices had reduced: nets were sold without subsidy and treatment kits had a 40% subsidy. The cost of the information, education, and communication campaign,  and distribution to wholesalers was about $1·70 per treated net or insecticide kit." Armstrong 2001, Pg 1242

      "We present results from the first assessment of a large scale social marketing programme of insecticide-treated nets on child survival in Africa, in an area of high-intensity malaria transmission. We have shown that social marketing with a high cost-recovery level is an effective way to deliver insecticide-treated nets. More than half of all infants in the DSS area were sleeping under evertreated nets in mid-2000—ie, 3 years after the start of the social marketing activities. Overall coverage of evertreated nets in the two districts was 18% in children younger than 5 years in mid-1999." Armstrong 2001, Pg 1246

      Gambia

      "National impregnated bednet programme In 1981, The Gambian Government initiated a national Primary Health Care (PHC) programme; all villages with a population of 400 or more were invited to join the scheme. Each participating village selected a village health worker and a traditional birthattendant who received 6 and 8 weeks’ training, respectively. In June-July, 1992, the NIBP was implemented in about half (221) of the PHC villages. Dipping of bednets was organised by Regional Health Teams and done by a village health worker assisted by a traditional birth-attendant and the head of the women’s group, supervised by community health nurses. Before the intervention, people were asked to wash their nets. 40 mL insecticide (20% permethrin) needed to treat each net was poured into a large plastic bowl and 2 litres of water added to give a permethrin concentration on nets of about 200 mg/m2." D'alessandro 1995, Pg 480

      "The difficulties of distributing insecticide at the right time of the year, of ensuring that insecticide is used at the correct dilution, and of treating all the nets in a village are substantial. The NIBP employed a manager (MKC), responsible for coordinating the programme, purchasing the insecticide, organising the health education campaign, and liasing with the different RHTs. However, at the local level, the NIBP was organised and implemented mainly by rural health teams. Despite the many logistical problems encountered, mortality in children was reduced significantly in villages where bednets were used and treated with insecticide, indicating that in these age groups, malaria is the most important cause of death, a view supported by review of postmortem questionnaires. D'alessandro 1995
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