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Biomedical subjects

Jayne Webster

Publications and source records attributed to Jayne Webster.

7 recordsLinked to original sources
PubMed2005

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.

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 CI(UTN)=0.166, CI(EPI)=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 CI(ITN)=0.435, mean CI(UTN)=0.158; p<0.001) and EPI (median CI(ITN)=0.435, CI(EPI)=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.

Africa↗
PubMed2005

Experience of targeting subsidies on insecticide-treated nets: what do we know and what are the knowledge gaps?

Widespread coverage of vulnerable populations with insecticide-treated nets (ITNs) constitutes an important component of the Roll Back Malaria (RBM) strategy to control malaria. The Abuja Targets call for 60% coverage of children under 5 years of age and pregnant women by 2005; but current coverage in Africa is unacceptably low. The RBM 'Strategic Framework for Coordinated National Action in Scaling-up Insecticide-Treated Netting Programmes in Africa' promotes coordinated national action and advocates sustained public provision of targeted subsidies to maximise public health benefits, alongside support and stimulation of the private sector. Several countries have already planned or initiated targeted subsidy schemes either on a pilot scale or on a national scale, and have valuable experience which can inform future interventions. The WHO RBM 'Workshop on mapping models for delivering ITNs through targeted subsidies' held in Zambia in 2003 provided an opportunity to share and document these country experiences. This paper brings together experiences presented at the workshop with other information on experiences of targeting subsidies on ITNs, net treatment kits and retreatment services (ITN products) in order to describe alternative approaches, highlight their similarities and differences, outline lessons learnt, and identify gaps in knowledge. We find that while there is a growing body of knowledge on different approaches to targeting ITN subsidies, there are significant gaps in knowledge in crucial areas. Key questions regarding how best to target, how much it will cost and what outcomes (levels of coverage) to expect remain unanswered. High quality, well-funded monitoring and evaluation of alternative approaches to targeting ITN subsidies is vital to develop a knowledge base so that countries can design and implement effective strategies to target ITN subsidies.

Africa↗
PubMed2003

Malaria control in complex emergencies: the example of East Timor.

Malaria control in complex emergencies forms part of the World Health Organization's Roll Back Malaria (RBM) initiative. The underlying principle is a partnership with other UN agencies and non-governmental organizations, with the RBM programme providing support to its implementing partners through a Technical Support Network. This innovative approach was applied for the first time in 1999-2000, following the return of stability and security to East Timor. The RBM programme assessed the malaria situation during the acute emergency phase and identified programme priorities. Two non-governmental organizations were subsequently invited to operate as implementing partners. Individual proposals were developed and funding obtained, but no overall organizational and planning framework was established. Implementation commenced quickly, addressing aspects of prevention, diagnosis and treatment. As East Timor progressed into the transitional phase towards independence, the programme was not realigned to the changing context. Absence of monitoring and evaluation was a significant factor contributing to the resulting continuation of emergency malaria control activities well into the transitional phase. East Timor's example of malaria control in complex emergencies provides important lessons: (i). partnership roles and responsibilities should be clearly defined from the beginning of the programme, (ii). planning, monitoring and evaluation should be instigated from the start with the aim to develop long-term strategies and policies, (iii). expert support is necessary to guide implementation at all stages, (iv). the flexibility to react to changing priorities should be ensured as the context of the emergency and the available health structure changes, and (v). the implementation process, and alternatives for continuation of activities once the RBM complex emergency partnership has terminated, should be clarified to all partners involved.

Antimalarials↗
PubMed2003

A health facility based case-control study of effectiveness of insecticide treated nets: potential for selection bias due to pre-treatment with chloroquine.

Case control studies offer an attractive way to assess the effectiveness of insecticide treated nets (ITN) under programme conditions but have the drawback of being susceptible to bias in the choice of controls. We evaluated the potential for pre-treatment with chloroquine to result in misclassification of cases and controls and affect estimates of ITN effectiveness in case control studies in urban and rural clinics in Eastern Afghanistan. During the one-month study, use of ITN showed no effect against malaria in the urban clinic (adjusted odds ratio OR 1.08; 95% CI 0.73-1.6) and the protective effect seen in the rural clinic was not significant (OR 0.62; 95% CI 0.2-2.4). Levels of pre-treatment were high in both clinics: 24% in urban and 19% in rural clinic attenders. In the urban clinic attenders the level of pre-treatment between bed net users and non-users was not significantly different (OR 1.07, 95% CI 0.70-1.64); therefore the misclassification of cases as controls did not introduce any selection bias. Amongst rural clinic attenders, bed net users were less likely to pre-treat with chloroquine than users (OR 0.33, 95% CI 0.14-0.77); this introduced a selection bias that resulted in an underestimation of the effectiveness of bed nets. Case control studies using health facility data are liable to selection bias especially in areas of high pre-treatment rates with chloroquine. Generalisation of results over a wide geographic region, or between urban and rural settings, may not be appropriate.

Adolescent↗
PubMed2002

Prevention of malaria in Afghanistan through social marketing of insecticide-treated nets: evaluation of coverage and effectiveness by cross-sectional surveys and passive surveillance.

Malaria is often a major health problem in countries undergoing war or conflict owing to breakdown of health systems, displacement of vulnerable populations, and the increased risk of epidemics. After 23 years of conflict, malaria has become prevalent in many rural areas of Afghanistan. From 1993 to the present, a network of non-governmental organizations, co-ordinated by HealthNet International, has operated a programme of bednet sales and re-treatment in lowland areas. To examine whether a strategy based on insecticide-treated nets (ITN) is a viable public health solution to malaria, communities were given the opportunity to buy nets and then monitored to determine population coverage and disease control impact. This was carried out using two contrasting methods: cross-sectional surveys and passive surveillance from clinics using a case-control design. Nets were purchased by 59% of families. Cross-sectional surveys demonstrated a 59% reduction in the risk of Plasmodium falciparum infection among ITN users compared with non-users (OR 0.41; 95% CI 0.25-0.66). The passive surveillance method showed a comparable reduction in the risk of symptomatic P. falciparum malaria among ITN users (OR 0.31; 95% CI 0.21-0.47). The cross-sectional method showed a 50% reduction in risk of P. vivax infection in ITN users compared with non-users (OR 0.50; 95% CI 0.17-1.49) but this effect was not statistically significant. The passive surveillance method showed a 25% reduction in the risk of symptomatic P. vivax malaria (OR 0.75; 95% CI 0.66-0.85). ITN appeared to be less effective against P. vivax because of relapsing infections; hence an effect took more than one season to become apparent. Passive surveillance was cheaper to perform and gave results consistent with cross-sectional surveys. Untreated nets provided some protection. Data on socioeconomic status, a potential confounding factor, was not collected. However, at the time of net sales, there was no difference in malaria prevalence between buyers and non-buyers. The abundance of Anopheles stephensi, the main vector, did not appear to be affected by ITN. ITN constitute one of the few feasible options for protection against malaria in chronic emergencies.

Adolescent↗