Higher HIV-1 incidence and genetic complexity along main roads in Rakai District, Uganda

OBJECTIVE: To determine the association between the incidence of HIV-1 infection and the genetic complexity of HIV-1 strains in 2 geographic strata within Rakai District, Uganda. METHODS: Study volunteers with recent HIV-1 infections during the period 1997 through 2003 were recruited from 10 communities that were geographically stratified as a main road trading center (n = 5) or a secondary road trading village (n = 5). Cryopreserved plasma was available from 384 volunteers and was the source of viral RNA for genotyping by the multiregion hybridization assay. Hazard ratios (HRs) for a single HIV subtype, a recombinant form, or dual infection for gender and geographic strata were obtained using Cox proportional hazards analysis. RESULTS: The HIV-1 incidence rate during the period 1999 through 2002 was 1.3 per 100 person-years (PYs) in the trading centers and 1.1 per 100 PYs in the trading villages. The HR for infection with an HIV-1 recombinant strain in trading centers relative to trading villages was 2.3 (95% confidence interval [CI]: 1.0 to 6.7). Among those who changed residence between village strata, the HR for a recombinant HIV-1 infection was 8.1 (95% CI: 0.4 to 47.7). CONCLUSIONS: HIV-1 incidence and genetic complexity are associated with geographic strata and population mobility in Rakai District and are important variables to be considered in planning and recruitment for vaccine trials.