Redefining the HIV epidemic in Nigeria: from national to state level.

BACKGROUND: Governments are increasingly recognizing the need to focus limited HIV resources on specific geographic areas and specific populations to have a greater impact. Nigeria, with the second largest HIV epidemic in the world, is an important example of where more localized programming has the potential to improve the efficiency of the HIV response. METHODS: Using Spectrum software we modelled the Nigerian HIV epidemic using two methods: First, we created national HIV estimates using trends in urban and rural areas. Second, we created national HIV estimates using trends from each of the 37 states in Nigeria and aggregated these results. In both instances we used HIV surveillance data from antenatal clinics and household surveys and aggregated the trends to determine the national epidemic. RESULTS: The state models showed divergent trends in the 37 states. Comparing the national results calculated from the two methods resulted in different conclusions. In the aggregated state files, adult HIV incidence in Nigeria was stable between 2005 and 2013 (change of -6%), whereas the urban and rural file suggested incidence was decreasing over the same time (change of -50%). This difference was also reflected in the HIV prevalence trends, although the two methods showed similar trends in AIDS-related mortality. The two models had similar adult HIV prevalence in 2013: 3.0% (2.0-4.5%) in the aggregated state files versus 3.2% (3.0-3.5%) in the urban/rural file. CONCLUSION: The state-level estimates provide insight into the variations of the HIV epidemic in each state and provide useful information for programme managers. However, the reliability of the results is highly dependent on the amount and quality of data available from each sub-national area.

Can the UNAIDS modes of transmission model be improved? A comparison of the original and revised model projections using data from a setting in west Africa.

OBJECTIVE: The UNAIDS modes of transmission model (MoT) is a user-friendly model, developed to predict the distribution of new HIV infections among different subgroups. The model has been used in 29 countries to guide interventions. However, there is the risk that the simplifications inherent in the MoT produce misleading findings. Using input data from Nigeria, we compare projections from the MoT with those from a revised model that incorporates additional heterogeneity. METHODS: We revised the MoT to explicitly incorporate brothel and street-based sex-work, transactional sex, and HIV-discordant couples. Both models were parameterized using behavioural and epidemiological data from Cross River State, Nigeria. Model projections were compared, and the robustness of the revised model projections to different model assumptions, was investigated. RESULTS: The original MoT predicts 21% of new infections occur in most-at-risk-populations (MARPs), compared with 45% (40-75%, 95% Crl) once additional heterogeneity and updated parameterization is incorporated. Discordant couples, a subgroup previously not explicitly modelled, are predicted to contribute a third of new HIV infections. In addition, the new findings suggest that women engaging in transactional sex may be an important but previously less recognized risk group, with 16% of infections occurring in this subgroup. CONCLUSION: The MoT is an accessible model that can inform intervention priorities. However, the current model may be potentially misleading, with our comparisons in Nigeria suggesting that the model lacks resolution, making it challenging for the user to correctly interpret the nature of the epidemic. Our findings highlight the need for a formal review of the MoT.

Additional health and development activities for community-directed distributors of ivermectin: threat or opportunity for onchocerciasis control?

We studied the involvement of community-directed distributors (CDDs) of ivermectin for onchocerciasis control in other health and development activities in Nigeria, Togo and Cameroon. Most CDDs (82%) were involved in additional activities, especially EPI, water and sanitation and community development projects. These activities did not take up much time and were not considered an important burden. Ivermectin treatment coverage did not decline with increasing number of additional activities. Other health programmes are interested in building on the experiences and structures of community-directed treatment with ivermectin and involving CDDs in their health programmes. Some, such as EPI, provide financial incentives. Incentives by other programmes may enhance the performance of CDDs when they are selected on the basis of their CDD status. CDDs, health personnel and community members have very positive attitudes towards greater involvement of CDDs in additional health and development activities. We conclude that additional activities for CDDs do not pose a threat to but rather provide an opportunity to strengthen sustainability and effectiveness of ivermectin treatment.