Type of partnership and heterosexual spread of HIV infection in rural Uganda: results from simulation modelling

The objective was to estimate the likely percentage of HIV infections that may be attributable to one-off partnerships (such as those between female s ex workers and their clients) and longer-term partnerships in rural Uganda. This was addressed by the application of a microsimulation model (SimulAID S) of the transmission dynamics of HIV infection, drawing on data from a po pulation cohort of 10,000 in rural Uganda. For a scenario reproducing docum ented characteristics of the study population in 1990, when adult HIV preva lence was 9%, and during subsequent follow up (1990-1994), when adult HIV i ncidence was 8 per 1000 person-years, the percentage of HIV infections in m en (women) attributed to one-off partnerships decreased from 96% (26%) duri ng 1980 to 67% (8%) in 1989 and 22% (5%) in 1994. Reducing HIV transmission between one-off partners early in an HIV epidemic may substantially limit the potential for the spread of HIV infection. At a later phase, prevention must also focus on control of transmission between longer-term HIV-discord ant partners.