HIV-1 diversity and prevalence differ between urban and rural areas in the Mbeya region of Tanzania

The objective was to characterize HIV-1 strains in a potential vaccine trial cohort (CODE) in the Mbeya region of southwest Tanzania. Study volunteers (n = 3096) were recruited from urban areas in Mbeya Town using two different recruitment strategies and in a nearby rural village. Cryopreserved plasma from 507 HIV-1 prevalent cases was the source of viral RNA for HIV-1 genotyping by the Multi-region Hybridization Assay the MHAacd and selected strains were confirmed by complete genome sequencing. The overall HIV-1 prevalence was 16.6% [95% confidence interval (CI) 15.3– 17.9] within the cohort. HIV-1 prevalence was higher among women and in urban areas. Recruitment through advertisement targeted a high-risk urban male population for HIV-1 infection [adjusted odds ratio (adj. OR) 1.68; 95% CI 1.13–2.51] when compared with men recruited door-to-door. The complexity of the HIV-1 epidemic was also higher in urban areas evidenced by the high-risk of HIV-1 infection with a recombinant strain (adj. OR 2.69; 95% CI 1.08–6.69) and HIV-1 dual infection (adj. OR 5.16; 95% CI 1.07–24.9) mainly driven by urban men recruited through advertisement. Overall the urban epidemic was more genetically complex with higher prevalence and more recombinants and dual infections. Vaccine trials in Mbeya region can assess a complex HIV-1 population dynamic and determine vaccine efficacy in relationship to the genetic diversity of HIV-1 strains that challenge vaccines. (authors)