Assessment of BED HIV-1 Incidence Assay in Seroconverter Cohorts: Effect of Individuals with Long-Term Infection and Importance of Stable Incidence

BACKGROUND: Performance of the BED assay in estimating HIV-1 incidence has previously been evaluated by using longitudinal specimens from persons with incident HIV infections, but questions remain about its accuracy. We sought to assess its performance in three longitudinal cohorts from Thailand where HIV-1 CRF01_AE and subtype B' dominate the epidemic. DESIGN: BED testing was conducted in two longitudinal cohorts with only incident infections (a military conscript cohort and an injection drug user cohort) and in one longitudinal cohort (an HIV-1 vaccine efficacy trial cohort) that also included long-term infections. METHODS: Incidence estimates were generated conventionally (based on the number of annual serocoversions) and by using BED test results in the three cohorts. Adjusted incidence was calculated where appropriate. RESULTS: For each longitudinal cohort the BED incidence estimates and the conventional incidence estimates were similar when only newly infected persons were tested, whether infected with CRF01_AE or subtype B'. When the analysis included persons with long-term infections (to mimic a true cross-sectional cohort), BED incidence estimates were higher, although not significantly, than the conventional incidence estimates. After adjustment, the BED incidence estimates were closer to the conventional incidence estimates. When the conventional incidence varied over time, as in the early phase of the injection drug user cohort, the difference between the two estimates increased, but not significantly. CONCLUSIONS: Evaluation of the performance of incidence assays requires the inclusion of a substantial number of cohort-derived specimens from individuals with long-term HIV infection and, ideally, the use of cohorts in which incidence remained stable. Appropriate adjustments of the BED incidence estimates generate estimates similar to those generated conventionally

Educational attainment and HIV-1 infection in developing countries: a systematic review.

OBJECTIVES: To assess whether educational status is associated with HIV-1 infection in developing countries by conducting a systematic review of published literature. METHODS: Articles were identified through electronic databases and hand searching key journals. Studies containing appropriately analysed individual level data on the association between educational attainment and HIV-1 status in general population groups were included. RESULTS: Twenty-seven articles with appropriately analysed results from general population groups in developing countries were identified, providing information on only six countries. Large studies in four areas in Africa showed an increased risk of HIV-1 infection among the more educated, whilst among 21-year-old Thai army conscripts, longer duration of schooling was strongly protective against HIV infection. The association between education and schooling in Africa was stronger in rural areas and in older cohorts, but was similar in men and women. Serial prevalence studies showed little change in the association between schooling and HIV over time in Tanzania, but greater decreases in HIV prevalence among the more educated in Uganda, Zambia and Thailand. CONCLUSIONS: In Africa, higher educational attainment is often associated with a greater risk of HIV infection. However, the pattern of new HIV infections may be changing towards a greater burden among less educated groups. In Thailand those with more schooling remain at lower risk of HIV infection