System effectiveness of a targeted free mass distribution of long lasting insecticidal nets in Zanzibar, Tanzania

Abstract

BackgroundInsecticide-treated nets (ITN) and long-lasting insecticidal treated nets (LLIN) are important means of malaria prevention. Although there is consensus regarding their importance, there is uncertainty as to which delivery strategies are optimal for dispensing these life saving interventions. A targeted mass distribution of free LLINs to children under five and pregnant women was implemented in Zanzibar between August 2005 and January 2006. The outcomes of this distribution among children under five were evaluated, four to nine months after implementation.MethodsTwo cross-sectional surveys were conducted in May 2006 in two districts of Zanzibar: Micheweni (MI) on Pemba Island and North A (NA) on Unguja Island. Household interviews were conducted with 509 caretakers of under-five children, who were surveyed for socio-economic status, the net distribution process, perceptions and use of bed nets. Each step in the distribution process was assessed in all children one to five years of age for unconditional and conditional proportion of success. System effectiveness (the accumulated proportion of success) and equity effectiveness were calculated, and predictors for LLIN use were identified.ResultsThe overall proportion of children under five sleeping under any type of treated net was 83.7% (318/380) in MI and 91.8% (357/389) in NA. The LLIN usage was 56.8% (216/380) in MI and 86.9% (338/389) in NA. Overall system effectiveness was 49% in MI and 87% in NA, and equity was found in the distribution scale-up in NA. In both districts, the predicting factor of a child sleeping under an LLIN was caretakers thinking that LLINs are better than conventional nets (OR = 2.8, p = 0.005 in MI and 2.5, p = 0.041 in NA), in addition to receiving an LLIN (OR = 4.9, p < 0.001 in MI and in OR = 30.1, p = 0.001 in NA).ConclusionsTargeted free mass distribution of LLINs can result in high and equitable bed net coverage among children under five. However, in order to sustain high effective coverage, there is need for complimentary distribution strategies between mass distribution campaigns. Considering the community's preferences prior to a mass distribution and addressing the communities concerns through information, education and communication, may improve the LLIN usage.

Strategies for delivering insecticide-treated nets at scale for malaria control: a systematic review

“…A total of 378 households in the Adjumani district of Uganda were surveyed 5-7 months after distribution of partially subsidized ITNs to pregnant women through antenatal care clinics 27 and 264 households in the North A district of Zanzibar were surveyed 5 months after ITN delivery during a stand-alone ITN campaign. 41 Responses revealed use by 94% of children under 5 in households surveyed in the Adjumani district and by 87% of children under 5 in the North A district.…”

“…3 and Table 2). Seven studies provided fully subsidized ITNs through a stand-alone campaign only (in one 41 ) or through an integrated campaign only (in six [42][43][44][47][48][49][50][51]. One study considered the continuous delivery of free ITNs through antenatal clinics.…”

“…The strategy evaluated in one delivered ITNs during a stand-alone campaign. 41 The other investigated a combined strategy involving delivery of fully subsidized ITNs to children under 5 through a campaign integrated with measles vaccination and partially subsidized ITNs to pregnant women through antenatal clinics. 29,30 In five studies, ITN ownership or use was higher in the least poor quintile.…”

“…[32][33][34][35] The fifth study reviewed a stand-alone ITN campaign involving distribution of fully subsidized nets to children under 5 in the Micheweni district of Zanzibar. 41 Table 2 shows the variety of study designs used to assess ITN delivery strategies. Of the 18 studies reporting data on ITN ownership among households and ITN use among children under 5, the study design in two (a cluster-randomized controlled trial [22][23][24] and a quasi-experimental study without randomization 21 ) involved comparison areas, and the study design in four involved a temporal comparison.…”

Use of Insecticide treated bed nets amongst Public Health Physicians in Nigeria

“…More recently, the goal has shifted to 'Universal Coverage', whereby every person living in a malarious area sleeps under an ITN, preferably a Long-lasting Insecticidal Net (LLIN) 4 . With the significant increase in funding in the recent decade, many countries across sub-Saharan Africa, including Nigeria, are rapidly increasing ITN ownership, through several strategies including, social marketing , 5,6.7 , free distribution to target groups (through antenatal care (ANC) or immunization campaigns [8][9][10][11][12] , and more recently, free universal population-based distribution campaigns targeting the entire population at risk 6,8,12,13,14 .…”