Post-natal incidence of HIV-1 infection among children in a rural Ugandan population: no evidence for transmission other than mother to child

We conducted a prospective cohort study to determine the post‐natal incidence of and possible transmission routes for HIV‐1 infection in rural Ugandan children. The cohort consisted of the population of a cluster of 15 villages in Masaka District, south‐west Uganda, and was enrolled in 1989–1990 through a demographic and serological survey. During the period 1991–1993 the population was resurveyed annually. A total of 5492 children aged 0–12 years were enrolled; of these, 41 (0.7%) were seropositive infants. A total of 3941 (72%) children were HIV‐negative on enrolment and had at least one follow‐up specimen. During 8596 person‐years of observation only 1 seroconversion was observed, an incidence rate of 0.12 (95% CI 0.00–0.35) per 1000 years of observation. The transmission of HIV was most probably through breast milk. The case corresponds to a rate of 1.1 per 1000 in households with one or more HIV‐positive adults (874 years of observation); no incident case was observed in households with only seronegative adults (6423 years of observation). Thus, HIV infection among children aged 0–12 years in this population is virtually exclusively the result of mother‐to‐child transmission. No infections were observed attributable to parenteral exposure, non‐sexual casual or household contact, or insects.