Kaiyuan Sex Workers Aids And Std Infection Rate And Its Epidemiological Factors

Background Sexual transmission has become the dominant route of human immunodeficiency virus (HIV) spread in China. HIV epidemic have been transmitted into general population, and female sex workers (FSWs) are important bridge population of HIV and sexually transmiited infections (STIs) transmission. In China, HIV/STIs prevalence among FSWs is ascending gradually, but HIV/STIs incidence among FSWs is exiguous.Objectives To estimate HIV/STIs incidence among FSWs and identify the risk factors related to HIV/STIs seroconversion. To investigate HIV/STIs prevalence, longitudinal trend and to explore the factors associated with HIV/STIs prevalence. Factors associated with drug initiation were analyzed among FSWs open cohort. To estimate the mobility of FSWs, and to investigate mobility pattern and the factors related to FSWs mobility.Methods Six-stage serial cross-sectional surveys were carried out every 6 months among FSWs between March 2006 and October in Kaiyuan city, Yunnan provice. The subjects who repeatedly participated in two or more serial cross-sectional surveys comprised an open-cohort. We collected information about socio-demographic characteristics, mobility, drug use behavior, reproductive health, health seeking and sexual behaviors. The blood was collected to test for HIV, herpes simplex virus-2 (HSV-2) and syphilis, urine specimen was collected to test for morphine, cervical secretions was collected to test for Gonorrhoea and Chlamydia trachomatis, vaginal secretions was collected to test for Trichomonas vaginalis.270 FSWs in a closed-cohort were recruited from subjects who have participated in the first cross-sectional survey. Once the participants were recruited into the cohort, they would be interviewed by telephone every month in the following 12 months. Logistic generalized estimating equations (GEE) model was used to determine the factors associated with prevalent HIV/STIs. And Cox proportional hazards regression model with time dependent variables was used to measure the associations between incident HIV/STIs, drug initiation and independent variables.Results (1) HIV prevalence were 10.3%(95% CI,8.2-12.7),11.9%(95% CI, 9.7-14.5),3.1%(95% CI,10.7-15.8),2.3%(95% CI,9.3-15.9),11.7%(95% CI, 9.2-14.6) and 12.2% (95% CI,9.6-15.2) among FSWs in six-stage serial cross-sectional surveys respectively. Analyzed with multivariate logistic GEE model, the factors associated with HIV infection were 21-25 years old (odds ratio, OR=2.0), 26-54 years old (OR=2.1), with registered permanent residence in other cities of Yunnan province (OR=1.9), working in low level entertainment (OR=1.5), extracting/filling/cleaning tooth (OR=1.5), injection drug users (IDUs, OR=9.2), non-injection drug users (OR=1.9), duration of sex work being 5 years or more (OR=1.6), perceived vulnerable to HIV infection (OR=1.3), emerging genital ulcers or wart last year (OR=2.4) and HSV-2 sero-positivity (OR=2.2). (2) In FSWs open cohort, the incidence density of HIV, HSV-2, syphilis, trichomonas vaginalis, neisseria gonorrhoeae, and chlamydia trachomatis were 1.2 cases per 100 person years (95%CI 0.62-2.20),26.1 cases per 100 person years (95% CI 20.7-32.1),1.3 cases per 100 person years (95% CI 0.67-2.24),6.3 cases per 100 person years (95% CI 4.80-8.12),5.6 cases per 100 person years (95% CI 4.17-7.25), and 16.8 cases per 100 person years (95% CI 14.1-19.7), respectively. Analyzed with Cox proportional hazard regression model, the factors associated with HIV seroconversion were non-injection drug users (hazard ration, HR=5.5,95% CI 1.37-22.30), the number of clients last week≥7 (HR=4.5,95% CI 1.34-14.85), syphilis sero-positivity (HR=4.3, 95% CI 1.06-17.61) and being infected with neisseria gonorrhoeae (HR=4.1,95% CI 1.04-16.26). (3) Totally 50 subjects initiated drug use among non-drug users FSWs, the incidence density of drug initiation was 6.7 cases per 100 person years (95% CI 5.04-8.79), and the factors related to drug initiation included low level entertainment (HR=1.8,95% CI 1.04-3.15), age of first sex≥18 years (HR=0.5,95% CI 0.27-0.81) and HIV sero-positive (HR=2.8,95% CI 1.24-6.13). (4) In FSWs close-cohort,117 (43.3%) FSWs moved to other cities to engage in sex work during the follow-up period and the incidence density of mobility was 5.1 cases per 100 person years (95% CI 4.27-6.12). Factors significantly coHRelated with FSWs mobility were low level entertainment (HR=0.6,95% CI 0.43-0.94) and perceived vulnerable to STIs infection (HR=0.7,95% CI 0.46-0.96). Conclusions HIV/STIs inicdeces among FSWs estimated separately by open cohort and closed cohort were unanimous. Because of the high mobility of FSWs, it was difficult to carry out closed cohort among FSWs, so open cohort shaped by serial cross-sectional studies should be used to estimate HIV/STIs incidence, analyze related factors and evaluate intervention efficacy. The overall mobility was high among FSWs, and the FSWs working in low level entertainment were less mobile, but with higher risk of being infected with HIV/STIs and HIV/STIs transmission, so specific interventions should be implemented according to the level of FSWs, focusing on FSWs who work in low level entertainment. FSWs in low level entertainment and HIV-positive subjectes were more likely to initiate drug use, so social supporting mechanism and better voluntary counseling and testing should be provided to reduce the incidence of drug initiation, especially for HIV-positive FSWs. HIV incidence was particularly high among FSWs in Kaiyuan city, Yunnan province, and sexual transmission has become the dominant route of HIV transmission among FSWs in Kaiyuan.