INCIDENCE OF HIV-1 INFECTION IN ADULTS AND SOCIODEMOGRAPHIC CHARACTERISTICS OF SEROCONVERTERS IN A RURAL-POPULATION IN UGANDA - 1990-1994

Background. To evaluate HIV-1 incidence among adults and socio-demogra phic risk factors in a rural population in Uganda, a prospective cohor t study was carried out. Methods. All consenting adult residents in a cluster of 15 neighbouring villages of the Masaka District of south-we st Uganda have been participating in annual socio-demographic and sero logical surveys since November 1989. Those who had a negative serostat us when they were first tested and had at least one serostatus assessm ent during the 4 years of follow-up (1990-1994) have been evaluated fo r HIV-1 seroconversion. Incidence rates have been calculated per 1000 person-years of observation and socio-demographic characteristics asse ssed for association with recent seroconversion. Results. At the basel ine survey, of 4175 adults with assessable serostatus (79% of all cens used adults), 342 (8.2%) were seropositive. During 12 588.2 person-yea rs of follow-up 89 seroconversions were identified corresponding to an incidence rate of 7.1 (95% CI :5.6-8.5). Overall rates were highest i n females aged 20-24 years (15.2) and in males aged 20-44 years (11.6) . There was a significant interaction between age and sex; the ratio o f the rate in females to that in males decreased from 3.3:1 to 0.5:1 w ith increasing age. Rates for males aged <greater than or equal to 20 years were four times higher than those for younger males. Other signi ficant socio-demographic correlates with risk included not belonging t o the majority tribe, non-Muslim religion and length of stay on compou nd of less than 10 years. Incidence rates did not show any clear trend s with time. Conclusion. These findings further emphasize the need for targeted interventions.