Household survey in two provinces in Viet Nam estimates HIV prevalence in an urban and a rural population.

A household-based population study interviewed 2,553 women and 1,984 men aged 15-49 years in urban (Ho Chi Minh City) and rural (Thai Binh) provinces in Viet Nam between July and August 2005. The survey response rate was high--approximately 97% of households and 93% of adults overall, with a >92% acceptance of HIV testing among eligible adults. The unadjusted estimated population HIV prevalence was 0.3% (confidence interval [CI]: 0.1-0.6%) in Thai Binh and 0.7% (CI: 0.3-1.3) in Ho Chi Minh City (HCMC), compared with the national estimates and projections of 0.352% and 1.250%, respectively, for 2005. The ratio of male-to-female prevalence was 10.5:1 in Thai Binh and 1.3:1 in HCMC. A low level of men reported purchasing sex in the last 12 months (2.4%) and there were low self-reports of sexually transmitted infections in all adults (5%). A correct knowledge of HIV/AIDS prevention methods was high in both provinces (83%), although only 24.8% of women knew of the use of antiretroviral therapy to prevent vertical transmission of HIV. The observed population prevalence was consistent with recent projections in Thai Binh, although lower than expected in HCMC, indicating the substantial downward revisions of projected population HIV prevalence may need to be extended. The unequal sex prevalence ratio is consistent with the projected trends of increasing male-to-female sexual transmission in urban areas. The results and experience of this study will inform future population based surveys in Viet Nam and the broader Asian region.