Screening for Acute HIV Infections and Estimating HIV Incidence among Female Sex Workers from Low-Grade Venues in Guangxi, China

BACKGROUND: Guangxi has become one of the provinces with the most severe HIV-1 epidemic in China, where heterosexual contact is the dominant transmission route. However, data of acute HIV infections and HIV incidence among female sex workers (FSWs) from low-grade venues are scant. METHODS: A cross-sectional survey was performed among FSWs from low-grade venues in Guangxi. HIV antibody screening was performed by rapid testing (RT). HIV antibody–negative specimens were screened by pooled nucleic acid amplification testing (NAAT) for acute HIV infections. HIV antibody-positive specimens were further analyzed by Western blot (WB), followed by an HIV-1 BED capture enzyme immunoassay (BED-CEIA) to identify the recent infections. HIV-1 incidence was estimated by the data of pooled NAAT and BED-CEIA, respectively. RESULTS: A total of 7936 FSWs were recruited and answered the questionnaires. We successfully collected the blood samples from 6469 (81.5%) participants, of which 139 (2.1%) were HIV antibody–positive and 6330 (97.9%) were HIV antibody-negative by RT. With pooled NAAT, 7 cases were found to be HIV RNA positive, representing an additional 5.0% of HIV-infected persons and an estimated HIV incidence of 1.45 (95% CI: 1.17–1.76) per 100 person years. There were 137 positive and 2 indeterminate by WB, of which 124 (90.5%) positive specimens were subjected to BED-CEIA testing identifying 28 recent infections. The HIV incidence determined by BED-CEIA testing was 1.04 (95% CI: 0.65–1.43) per 100 person years. The overall prevalence of HIV among FSWs from low-grade venues in Guangxi was 2.2% (95% CI: 1.9–2.6). CONCLUSIONS: We found that the addition of HIV RNA screening to routine HIV antibody testing significantly improved the detection of HIV infection among FSWs from low-grade venues in Guangxi. Our findings also provided the useful baseline data of HIV incidence among this population for targeting local HIV prevention, intervention, monitoring and treatment.