HIV control in a new era: Exploring the potential impact of alternative intervention strategies in Uganda

Lead Research Organisation: London Sch of Hygiene and Trop Medicine
Department Name: Infectious and Tropical Diseases

Abstract

Uganda has been successful in controlling its HIV epidemic, but recent data suggest that this decline is not continuing, that HIV incidence has stabilised and that HIV prevalence may be rising again. Renewed efforts are needed to build on past successes and to inform policy on the most effective mix of HIV interventions. This project aims to compare the impact that different HIV control strategies are likely to have on the HIV epidemic in Uganda. The research will combine rigorous analysis of empirical data from Uganda with mathematical modelling of the epidemic. Epidemiological modelling is a powerful tool that can be used to help predict the impact of health intervention strategies on an epidemic, as well as to examine the role of various sub-populations or behaviours in establishing the current epidemic. The project will be carried out in three stages. First, existing data will be used to establish a range of plausible values for input parameters influencing the progression of the epidemic. Second, these input parameters will be varied within the established plausible ranges until the model provides a good fit to empirical data on the progression of incidence and prevalence over time. Third, once the model is fitted, researchers will simulate a variety of control strategies to predict the impact that these interventions will have on the HIV epidemic. To validate the models, extensive longitudinal data available from the MRC Unit and other sources in Uganda will be used, as well as additional data that will become available during the course of the project. The additional sources of data include a sex worker cohort in Kampala, and trials of a vaginal microbicide, male circumcision and ante-retroviral therapy. Five specific intervention strategies will be assessed: male circumcision, use of vaginal microbicides, treatment of sexually transmitted diseases, behavioural change and anti-retroviral therapy. Combinations of these interventions will also be assessed. The impact of these interventions will be assessed in two areas of Uganda ? Kyamulibwa, a typical rural area, and Kampala, the capital of Uganda. To ensure that the results of the research influence public health policy, policy makers in Uganda will be involved in this project from the outset.

Technical Summary

Until recently, Uganda has been successful in controlling its HIV epidemic, with HIV prevalence and incidence falling for several years. However, recent data suggest that this decline is not continuing, that HIV incidence has stabilised and that HIV prevalence may be rising again. New efforts are therefore needed to build on past successes, and to identify the most effective HIV control strategies for the future. These may differ from past strategies, since HIV transmission dynamics vary with the phase of the epidemic. The proposed project aims to compare the projected impact of different interventions on the HIV epidemic in the new epidemiological context of stabilising prevalence following several years of decline. This research will use the wealth of extensive longitudinal data available from MRC Uganda and other sources, in combination with deterministic and stochastic mathematical models. During the course of the project, additional data will become available from a sex worker cohort in Kampala and trials of a microbicide gel, male circumcision and ante-retroviral therapy. Five specific intervention strategies will be investigated: male circumcision, use of vaginal microbicides, treatment of sexually transmitted diseases, behavioural change, and anti-retroviral therapy. Combinations of these interventions will also be assessed. The project will assess the effects of interventions in the general population, as well as targeted interventions in high-risk groups that may play an increasing role in HIV transmission in a declining epidemic.

Publications

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Baggaley RF (2008) Systematic review of orogenital HIV-1 transmission probabilities. in International journal of epidemiology

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Kretzschmar M (2010) Concurrency is more complex than it seems. in AIDS (London, England)

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Mwita W (2008) Has the HIV epidemic in rural Mwanza, Tanzania reached a plateau? in Tanzania journal of health research

 
Description Male circumcision services for HIV prevention
Geographic Reach Africa 
Policy Influence Type Membership of a guidance committee
Impact Directly influenced formation of WHO/UNAIDS guidelines on scale up of male circumcision services for HIV prevention in Africa
 
Description MRC Research Methodology Fellowship
Amount £424,404 (GBP)
Organisation Medical Research Council (MRC) 
Sector Academic/University
Country United Kingdom
Start  
 
Description WHO Project grant
Amount £17,700 (GBP)
Organisation World Health Organization (WHO) 
Sector Public
Country Global
Start  
 
Title New mathematical models of STI/HIV spread and control 
Description Compartmental and individual-level mathematical models of STI/HIV spread 
Type Of Material Model of mechanisms or symptoms - human 
Provided To Others? No  
Impact Papers are being prepared or are under review describing the methods and findings using these new models. These new models are currently being adapted for use in subsequent research projects including estimating the impact of vaccination on the incidence of HPV and cervical cancer in Europe. 
 
Description Centre for the Mathematical Modelling of Infectious Diseases 
Organisation Public Health England
Department Centre of Infectious Disease Surveillance and Control
Country United Kingdom 
Sector Public 
PI Contribution Set up the Centre. Regularly hold scientific presentations and methodology workshops, journal club.
Collaborator Contribution Fostered exchange of mathematical modelling expertise between LSHTM and HPA
Impact This Centre had raised the profile of mathematical modelling work carried out in LSHTM, HPA and in MRC Uganda
Start Year 2006
 
Description MRC/UVRI Uganda Research Unit on AIDS on HIV in Uganda 
Organisation MRC/UVRI Uganda Research Unit on AIDS
Country Uganda 
Sector Public 
PI Contribution Co-writing of proposal, data analysis and modelling training of staff or significant intellectual input into the research.
Collaborator Contribution Data, equipment or facilities, and significant intellectual input into the research.
Impact 17522260, 19901974, 18032935, 19307338, 18670225, 19024335, 17457106, School visit - Uganda (non academic) New mathematical models of STI/HIV spread and control
 
Description PhD Fellowships with the UK Heath Protection Agency 
Organisation Public Health England
Department Centre of Infectious Disease Surveillance and Control
Country United Kingdom 
Sector Public 
PI Contribution Has fostered flow of modelling expertise between HPA and LSHTM
Collaborator Contribution Has fostered flow of modelling expertise between HPA and LSHTM
Impact Two PhD Fellowships ongoing between LSHTM and HPA.
Start Year 2008
 
Description School visit - uganda 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Schools
Results and Impact School visit. Rebecca Nusuba and Leigh Anne Shafer (both MRC Uganda) put together and presented material on the mathematical modelling of infectious diseases for a schools visit. Attendees: advanced high school students and early undergraduates
Event explained the utility of mathematical modelling of infectious diseases.

Large number of students exposed to mathematical modelling.
Year(s) Of Engagement Activity 2009