Review
Which delivery systems reach the poor? A review of equity of coverage of ever-treated nets, never-treated nets, and immunisation to reduce child mortality in Africa

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Summary

Insecticide-treated nets (ITNs) and childhood vaccination are two of the most powerful interventions available to prevent childhood mortality in Africa, but ITN coverage is still very low. Current debates about how to increase ITN coverage are concerned with the roles of different supply and delivery systems, in particular whether or not commercial net markets have any useful role. Here, we review data available on coverage and equity of coverage of three interventions to prevent childhood mortality. We compiled and analysed data from nationally representative surveys in 26 African countries to compare equity of coverage of (1) the Expanded Programme on Immunisation (EPI), (2) any net, (3) ever-treated nets (ie, ITNs), and (4) never-treated nets (ie, untreated nets; UTNs). We assumed that ever-treated net coverage mostly reflects the activities of public-health programmes and projects, and that never-treated net coverage mostly reflects the activity of local unsubsidised commercial markets. We discuss the validity, limitations, and possible biases of these assumptions. We estimate that 87% of the 8·4 million children protected by nets used UTNs. We used the concentration index (CI) to assess equity of coverage of the interventions. The data shows that never-treated net coverage is surprisingly equitable: overall, and despite substantial regional variations, it is comparable in equity to EPI (median CIUTN=0·166, CIEPI=0·075; p=0·3). In almost all countries, coverage of ITNs is strongly concentrated in the least poor households, and significantly more inequitable than both UTNs (median CIITN=0·435, mean CIUTN=0·158; p<0·001) and EPI (median CIITN=0·435, CIEPI=0·075; p<0·001). These results suggest that the public-health value of commercial net markets has been greatly underestimated, and that these markets have so far contributed more to equitable and sustainable coverage of mosquito nets, and hence to the prevention of malaria in Africa, than have the ITNs delivered by public-health systems and projects.

Introduction

In the poorer countries of the world, a large proportion of child mortality is caused by a few preventable diseases. Effective interventions against these diseases exist,1 but the Millennium Development Goal of reducing child mortality by two-thirds by the year 2015 will not be achieved unless there is a massive increase in the coverage of these interventions,2 especially in the poorest and most vulnerable groups.3

Two of the most powerful preventive interventions against child mortality in Africa are insecticide-treated nets (ITNs) and childhood immunisation. During the 1970s and 1980s, greatly improved immunisation rates were achieved by the Expanded Programme on Immunisation (EPI). Although coverage rates have been declining recently in some countries, particularly poor countries,2 EPI is still justifiably regarded as a public-health success story.

Strategies for increasing ITN coverage, by contrast, are a relatively recent development, and are still the subject of active debate. There is general agreement that subsidised access to ITNs should be provided on a large scale and in the long term, but disagreement exists over how these subsidies should be deployed. A central issue in this debate is the actual and potential contribution of unsubsidised commercial markets, including existing local markets in untreated nets (UTNs), and whether or not these markets should be included in the design of systems for delivering subsidies.

Some experts doubt the capacity of public-health delivery systems on their own to achieve full ITN coverage throughout Africa, and the capacity of donor financing to sustain this goal. The net coverage achieved by existing commercial markets is potentially valuable, because it provides public-health benefits in a sustainable way and at no public cost, thereby freeing public money for other vital interventions such as treatment with effective antimalarial drugs. A mixed strategy could therefore be proposed in which there is the maximum possible level of subsidised provision targeted to the economically or biologically vulnerable, but the system used to deploy these subsidies is designed to preserve, and where possible to encourage, existing commercial net markets.4 For example, current programmes are testing the use of vouchers that allow recipients (eg, pregnant women attending antenatal clinics) to buy ITNs at a heavily subsidised price from commercial retail sources.

Other experts believe that ITNs should be provided free of charge to everyone at risk in Africa using donor funding.5 They are sceptical about the value and potential of commercial markets, which they see as serving mainly the urban rich, and as contributing little towards protection of the rural poor who suffer most from malaria. Instead, they argue that ITNs are of comparable cost-effectiveness to EPI vaccinations and they should be delivered in the same way: free of charge through the public sector.5

Since people have to pay for nets supplied through unsubsidised commercial markets, but not for EPI vaccinations, it is reasonable to expect EPI coverage to be more equitable—that is, more equally distributed among richer and poorer households—than commercial net coverage. However, remarkably little is known about commercial net markets in Africa and the pattern of net coverage that they support. The assertion that these markets do not serve the rural poor has not been supported by large-scale quantitative data on coverage. We attempt to fill this gap in the evidence.

Our starting point was the data on net coverage in 28 countries published in the WHO's Africa malaria report.6 According to the report, the number of children under the age of 5 years sleeping under an ITN was seven times lower than the number sleeping under any kind of net. This finding was surprising, because public-health programmes and projects generally distribute ITNs, and very rarely distribute nets without insecticide. Moreover in most African countries, public-health programmes are the only important and large-scale sources of ITNs, and the nets made by local suppliers are almost all untreated. The treatment history of an individual net—whether or not it has ever been treated—therefore gives information about its source. We based our analysis on the assumption that most of the ITNs reported in these surveys were originally supplied by a public-health programme or project, while most of the UTNs were bought at unsubsidised prices from local commercial suppliers. We collated data from recent nationally representative surveys in Africa, and analysed the information on coverage of children with nets (treated and untreated) and with immunisation. In particular, we tried to test two hypotheses. First, that public-health programmes and projects, which in the past have mostly sold imported ITNs at subsidised prices, have achieved more equitable net coverage than local commercial net suppliers and traders, which mostly sell UTNs at unsubsidised prices. Second, that the coverage produced by these local commercial markets in UTNs is also less equitable than that of EPI, which is delivered free of charge.

Section snippets

Methods

Data on national coverage from demographic and health surveys and multiple-indicator cluster surveys were extracted from their respective websites.7, 8 Demographic and health surveys and multiple-indicator cluster surveys are nationally representative household surveys in which questions are asked of women and the children for whom they are caretakers. Data are collected at the household level on all children under the age of 5 years. Our analysis focused on coverage of young children with (1)

Results

The data on intervention coverage are presented in figure 2. Each of the charts represents one country dataset, and shows the percentage coverage for each intervention, by socioeconomic quintile, within that country. Summary statistics on overall coverage and CI are presented in table 1.

There was considerable variation across countries in the coverage of all interventions. In general, EPI coverage was much higher (median 48%, range 13–78%) than any-net coverage (median 15%, range 1–67%);

Discussion

The data indicate that in the surveyed countries 87% of the nets covering young children have never been treated with insecticide. Our analysis strongly contradicts our first hypothesis, that the delivery of ITNs by subsidised programmes is more equitable than the delivery of UTNs by unsubsidised commercial markets. In fact, ever-treated net coverage was strongly biased towards richer households in almost all countries, wherease never-treated net coverage was generally much more equitable,

Search and selection criteria

We searched for nationally representative surveys in sub-Saharan African countries containing data on immunisation and the use of nets by children under 5 years of age, together with the treatment status of those nets, and the socio-economic status of the households. The analysis includes the most recent surveys publicly available in Sept 2004, excluding those done before 1999.

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