Modelling HIV/AIDS Epidemics in Botswana and India: Impact of Interventions to Prevent Transmission (*). (Theme Paper)

Article excerpt

Objective To describe a dynamic compartmental simulation model for Botswana and India, developed to identify the best strategies for preventing spread of HIV/AIDS.

Methods The following interventions were considered: a behavioural intervention focused on female sex workers; a conventional programme for the treatment of sexually transmitted infections; a programme for the prevention of mother-to-child transmission; an antiretroviral treatment programme for the entire population, based on a single regimen; and an antiretroviral treatment programme for sex workers only, also based on a single regimen.

Findings The interventions directed at sex workers as well as those dealing with sexually transmitted infections showed promise for long-term prevention of human immunodeficiency virus (HIV) infection, although their relative ranking was uncertain. In India, a sex worker intervention would drive the epidemic to extinction. In Botswana none of the interventions alone would achieve this, although the prevalence of HIV would be reduced by almost 50%. Mother-to-child transmission programmes could reduce HIV transmission to infants, but would have no impact on the epidemic itself. In the long run, interventions targeting sexual transmission would be even more effective in reducing the number of HIV-infected children than mother-to-child transmission programmes. Antiretroviral therapy would prevent transmission in the short term, but eventually its effects would wane because of the development of drug resistance.

Conclusion Depending on the country and how the antiretroviral therapy was targeted, 25-100% of HIV cases would be drug-resistant after 30 years of use.

Keywords HIV infections/epidemiology/prevention and control/drug therapy; Disease outbreaks/prevention and control; Disease transmission//prevention and control/prevention and control; Computer simulation; Models, Theoretical; Botswana; India (source: MeSH, NLM).

Mots cles HIV, Infection/epidemiologie/prevention et controle/chimiotherapie; Epidemie/prevention et controle; Transmission maladie/prevention et controle; Simulation ordinateur; Modele theorique; Botswana; Inde (source: MESH, INSERM).

Palabras clave Infecciones por VIH/epidemiologia/prevencion y control/quimioterapia; Brotes de enfermedades/prevencion y control; Transmision de enfermedad/prevencion y control; Simulacion por computador; Modelos teoricos; Botswana; India (fuente: DeCS, BIREME).

Bulletin of the World Health Organization 2002;80:89-96.

Resume

Modelisation de l'epidemie de VIH au Botswana et en Inde: impact des interventions destinees a empecher la transmission

Objectif Decrire un modele compartimental dynamique de simulation pour le Botswana et l'lnde, elabore dans le but d'identifier les meilleures strategies de prevention de la propagation du virus de l'immunodeficience humaine (VIH).

Methodes Les interventions suivantes ont ete examinees: une intervention comportementale axee sur les prostituees; un programme classique de traitement des infections sexuellement transmissibles; un programme de prevention de la transmission mere-enfant; un programme de traitement antiretroviral destine a l'ensemble de la population et reposant sur un schema therapeutique unique; un programme de traitement antiretroviral axe uniquement sur les prostituees et reposant egalement sur un schema therapeutique unique.

Resultats L'intervention axee sur les prostituees et celle axee sur les infections sexuellement transmissibles sont interessantes du point de vue de la prevention a long terme de l'infection a VIH, mais on ne sait pas exactement laquelle serait la plus efficace. En Inde, une intervention axee sur les prostituees pourrait conduirea a l'extinction de l'epidemie. Au Botswana, aucune intervention n'y parviendrait a elle seule, mais la prevalence du VIH pourrait baisser de pres de 50 %. Les programmes axes sur la transmission mere-enfant pourraient reduire la transmission du VIH aux nourrissons, mais n'auraient aucun impact sur l'epidemie elle-meme. …