Background: Survival patterns after HIV infection in African populations in the era before antiretroviral therapy (ART) form an important baseline for measuring future successes of treatment programmes. Few studies have followed seroconverters for 10 or more years to describe such patterns. Methods: The Kisesa open cohort study conducted four rounds of village-based HIV testing and 20 rounds of household-based demographic surveillance between 1994 and 2006. Approximate infection dates were established for individual seroconverters by allocating a date between the last negative and first positive test. Person-years lived post-infection were computed, allowing for left truncation and right censoring, and Kaplan–Meier survival functions were constructed, truncating the analysis at the start of 2005 when ART first became available in the community. Weibull models were fitted to estimate median survival time, and parametric regression methods were used to investigate the influence of sex and age at infection. Results: A total of 369 seroconverters were identified, providing 890 person-years of follow-up during which 44 deaths were observed. The Kaplan–Meier function showed 67% surviving 9 years post-infection, and the overall predicted median survival was 11.5 years. Survival was strongly related to age at infection (hazard ratio 1.06 for each additional year of age, and weakly to sex. A strong effect of age was evident even after allowing for mortality from non-HIV-related causes using cause deletion methods to estimate net mortality. Conclusion: The survival of HIV-infected individuals was comparable to that reported in developed country studies before the introduction of HAART. Survival patterns in Kisesa are marginally more favourable than those reported in cohort studies in Uganda.
In Brief Background: Persons with absent partners may be more vulnerable to risky sexual behavior and therefore HIV. Partner absence can be due to traveling (e.g., family visits or funerals) or to living apart (e.g., work-related or in polygamous marriages). We investigated to what extent partner absence leads to more risky sexual behavior in Tanzanian couples. Methods: We compared 95 men and 85 women living apart with 283 men and 331 women living together. Only persons who were still married were included, either living apart or cohabiting at the time of the interview. Subjects were classified into 4 groups: coresidents being either nonmobile or mobile, and people living apart either frequently or infrequently seeing each other. Results: Most people living apart were polygamously married. Men living apart did not report more extramarital sex than coresident men. However, among coresident men, extramarital sex was reported by 35% of those being mobile compared with 15% of those nonmobile. Among women, those living apart reported extramarital sex more often than coresidents (14% vs. 7%), and this was mainly due to women living apart who infrequently saw their husbands. Conclusions: Risky sexual behavior occurs more often in mobile coresident men, and in women living apart infrequently seeing their spouses. These groups are relatively easy to identify and need extra attention in HIV prevention campaigns. Among Tanzanian couples who live separated, only mobile coresident men, and women living apart and infrequently seeing their spouses, report significantly increased risky sexual behavior.
Background: Tanzanian antenatal clinic surveillance data suggest stabilizing HIV levels. Data from an open cohort in northern Tanzania provide robust estimates of prevalence and incidence. Methods: Between 1994 and 2004, 19 rounds of household-based demographic surveillance and 4 rounds of individually linked HIV serologic surveys were conducted. Longitudinal knowledge of individuals' testing histories is used to allow for effects of selective participation on prevalence estimates; multiple imputation procedures allow for interval censoring effects on incidence. Results: A total of 16,820 adults donated blood for HIV testing in at least 1 of 4 serologic surveys. HIV prevalence increased steadily from 6.0% in 1994/1995 to 8.3% in 2000/2001, leveling out thereafter. HIV incidence increased sharply from 0.8% in 1994 to 1997 to 1.2% per thousand in 1997 to 2000, remaining high (1.1%) in 2000 to 2003. In roadside areas, incidence fell in the last interval, especially among women, but in remote rural areas, incidence rose slightly. Conclusions: HIV spread is continuing in rural areas, suggesting a need for more intensive HIV prevention efforts and antiretroviral interventions. The leveling off in prevalence is attributable to a combination of high mortality among HIV-infected persons and a slight decrease in incidence in roadside villages.