Seven-year trends in HIV-1 infection rates, and changes in sexual behaviour, among adults in rural Uganda.

Abstract

To assess trends in HIV-1 infection rates and changes in sexual behaviour over 7 years in rural Uganda. An adult cohort followed through eight medical-serological annual surveys since 1989-1990. All consenting participants gave a blood sample and were interviewed on sexual behaviour. On average, 65% of residents gave a blood sample at each round. Overall HIV-1 prevalence declined from 8.2% at round 1 to 6.9% at round 8 (P = 0.008). Decline was most evident among men aged 20-24 years (11.7 to 3.6%; P < 0.001) and women aged 13-19 (4.4% to 1.4%; P = 0.003) and 20-24 (20.9% to 13.8%; P = 0.003). However, prevalence increased significantly among women aged 25-34 (13.1% to 16.6%; P = 0.04). Although overall incidence declined from 7.7/1000 person-years (PY) in 1990 to 4.6/1000 PY in 1996, neither this nor the age-sex specific rates changed significantly (P > 0.2). Age-standardized death rates for HIV-negative individuals were 6.5/1000 PY in 1990 and 8.2/1000 PY in 1996; corresponding rates for HIV-positive individuals were 129.7 and 102.7/1000 PY, respectively. There were no significant trends in age-adjusted death rates during follow-up for either group. There was evidence of behaviour change towards increase in condom use in males and females, marriage at later age for girls, later sexual debut for boys and a fall in fertility especially among unmarried teenagers. This is the first general population cohort study showing overall long-term significant reduction in HIV prevalence and parallel evidence of sexual behaviour change. There are however no significant reductions in either HIV incidence or mortality.