Guowei Ding

Prevalence and predictors of HIV infection among female sex workers in Kaiyuan City, Yunnan Province, China

BACKGROUND Sexual transmission is the fastest growing route of HIV transmission in China. We undertook this study to describe the risk factors for HIV infection in female sex workers (FSWs), and to determine the commercial sex venues where FSWs are most at risk of being infected with or infecting others with HIV. METHODS This was a cross-sectional study of 737 FSWs in Kaiyuan City, Yunnan Province in southern China, which took place from March to May 2006. RESULTS The overall HIV prevalence was 10.3%, but prevalence varied with sex venue with 25.8% of FSWs working on the streets being HIV-positive and none of the FSWs working in nightclubs. Adjusted odds ratios (OR) of HIV infection were 9.1 (95% confidence interval (CI) 4.67-17.55) for injection drug use, 3.3 (95% CI 1.46-7.37) for non-injection illegal drug use, 2.7 (95% CI 1.25-5.93) for duration of sex work > or = 5 years, 2.2 (95% CI 1.05-4.70) for infection with herpes simplex virus type 2, and 2.0 (95% CI 1.12-3.47) for working at a higher risk entertainment venue. Although condom use was not a significant risk factor in the overall model, FSWs in lower risk venues who reported consistent use with clients had a 70% reduction in HIV infections (OR 0.30, 95% CI 0.12-0.90). CONCLUSIONS Illegal drug use, particularly with injection drugs, is the single greatest risk factor for HIV infection among FSWs in Kaiyuan City, China. FSWs working on the street or in temporary sub-lets, beauty salons, or saunas are at particularly high risk for transmitting and being infected with HIV. HIV prevention efforts among FSWs should target illegal drug users and these other subgroups.

HIV prevalence and risk behaviors among male clients of female sex workers in Yunnan, China

Objectives:To assess the prevalence and risk factors of HIV among male clients of female sex workers (FSWs) in China. Methods:Convenience sampling methods were used to recruit 315 clients using FSW-client and client-client networks. Subjects provided information on sociodemographic characteristics and sexual and drug behavior patterns. Blood samples were collected for HIV testing and urine samples for opiate testing. Results:Overall HIV prevalence was 6.0%; among drug users, it was 30.8%. 33.7% of respondents reported that they always use condoms in commercial sex and 63.5% that they used a condom in the last commercial sex episode. Drug use (OR: 6.1; 95% CI: 1.7 to 21.4) and lack of a regular sexual partner (OR: 6.3; 95% CI: 1.8 to 21.9) were significantly associated with HIV infection. Conclusions:Clients of FSWs serve as potential bridges for HIV transmission from the high-risk FSWs to the low-risk general population, making them a key target for intervention. High HIV prevalence rates among clients in Kaiyuan is particularly alarming given their risk behavior patterns including high rates of partner exchange, low condom use rates, and drug-using behaviors. Innovative interventions are needed to reduce the risk of HIV among clients and reduce the bridge of transmission to the general population.

Prevalence and predictors of herpes simplex virus type 2 infection among female sex workers in Yunnan Province, China

Summary: The objective of this study was to determine the seroprevalence of herpes simplex virus type 2 (HSV-2), and to evaluate the relationship between HSV-2 infection and sociodemographic factors and the sexual practices of female sex workers (FSWs) in Kaiyuan city, Yunnan Province, China. This cross-sectional study involved 737 FSWs and was carried out from March to May 2006 with confidential interviews and laboratory tests for HSV-2 and other sexually transmitted infections (STI). HSV-2 was the most common STI (68%), followed by Chlamydia trachomatis (26%), Trichomonas vaginalis (11%), Neisseria gonorrhoeae (8%) and syphilis (7%). Prevalence of HIV-1 was 10.3%. Adjusted odds ratios of HSV-2 seroprevalence were 2.6 (95% CI [confidence interval]: 1.30-5.38) for HIV-1 infection, 2.0 (95% CI: 1.33-3.16) for vaginal douching, 2.0 (95% CI: 0.45-0.86) for condom breaking or falling off during sexual intercourse with the client in the previous week, 1.8 (95% CI: 1.07-3.18) for ≥5 years of commercial sex work, 1.6 (95% CI: 1.08-2.33) for ≥5 clients in the previous week, 0.6 (95% CI: 0.45-0.86) for ≥9 years of education. This study identifies a very high prevalence of HSV-2 infections among FSWs in Yunnan Province, with only a few who reported a prior history of genital herpes. HSV-2 serological screening and suppressive therapy should be considered for study populations. Education on the importance of diagnosis, treatment and prevention may help control the spread of HSV-2 infection.

Mobility, risk behavior and HIV/STI rates among female sex workers in Kaiyuan City, Yunnan Province, China

BackgroundThe mobility of female sex workers (FSWs) is a factor in the geographic spread of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). This study describes FSW mobility patterns in a high risk area of China to identify factors associated with increased mobility, and to study the incidence and prevalence of HIV/STIs in this group.Methods270 FSWs recruited from a baseline cross-sectional study were invited to participate in a one-year monthly follow-up cohort study in Kaiyuan City, Yunnan Province, China from 2006 to 2007. Laboratory tests were conducted for HIV/STIs at baseline, 6 and 12 months.ResultsA total of 117 (43.3%) FSWs moved to another city during the year. Risk factors for increased mobility included being from another city within Yunnan (adjusted hazard ratio [AHR] 1.67, 95% confidence interval [CI] 1.09-2.56), being from outside Yunnan (AHR 1.58, 95% CI 1.04-2.54), and working in lower risk entertainment establishments (AHR 1.55, 95% CI 1.03-2.35). HIV-positive subjects, drug users and FSWs in higher risk venue were less likely to change residence, less likely to use condoms with clients, and earned less per client, but had more working locations and more clients each month.ConclusionsThe least mobile FSWs were from Kaiyuan, worked in higher risk venues, were more likely to use drugs and be HIV-infected. Because FSWs characteristics differ according to the venue at which they work, future prevention work should tailor programs according to venue with a particular focus on FSWs in higher risk venues.

Factors Associated With HIV Testing History and HIV-Test Result Follow-up Among Female Sex Workers in Two Cities in Yunnan, China

Background: The majority of people living with HIV/AIDS in China are unaware of their serostatus, and increasing the utilization of HIV testing may help to control the epidemic. Methods: This longitudinal study was conducted among female sex workers (FSWs) in 2 cities in Yunnan Province, China. Participants were surveyed in face-to-face interviews and tested for HIV and STDs. Factors associated with HIV-testing history and HIV-test follow-up were analyzed. Results: Of the 1642 study participants, 291 (17.7%) had been previously tested and 868 (52.9%) returned for post-test follow-up. Factors associated with having a previous HIV test included attending the Kaiyuan study (aOR: 4.9, 95% CI: 2.3–10.1), ≥9 years of schooling (aOR: 10.9, 95% CI: 2.6–45.5), <5 clients in the recent week (aOR: 1.7, 95% CI: 1.2–2.3), having a regular sexual partner (aOR: 1.9, 95% CI: 1.4–2.5), illegal drug use history (aOR: 2.2, 95% CI: 1.5–3.1), pelvic pain in the past 12 months (aOR: 1.9, 95% CI: 1.1–3.6), HIV-seropositivity (aOR: 1.8, 95% CI: 1.2–2.8), and high perception of HIV risk (aOR: 1.5, 95% CI: 1.1–2.2). FSWs who had ≥9 years of schooling (aOR: 1.4, 95% CI: 1.1–1.9), had <5 clients in the recent week (aOR: 1.3, 95% CI: 1.1–1.6), or were from another province (aOR: 1.9, 95% CI: 1.4–2.5) or city (aOR: 1.4, 95% CI: 1.1–1.8) were more likely to follow-up. Conclusions: The low HIV-testing history and follow-up rates found in this is study is a significant public health problem as many high-risk individuals are not aware of their serostatus. Immediate action needs to be taken to increase the utilization of HIV testing services and notify people of their HIV status.

Tracking the Evolution of HIV/AIDS in China from 1989–2009 to Inform Future Prevention and Control Efforts

Background To determine policy implications, this analysis tracks the evolution of HIV/AIDS infection across China to understand current trends and potential risk factors. Methods and Principal Findings A retrospective study with spatial analytical model and multilevel spatial models was conducted among 326,157 HIV/AIDS cases reported from 1989–2009. The results indicate that the distribution of HIV/AIDS was clustered at the county level with different directional distributions across China from 2003 to 2009. Compared to 2003, by 2009 there was a 122% increase in HIV cases among rural residents, 294% increase among urban residents, 211% increase among migrants, and 237% increase among permanent residents. The overall proportion of HIV by different routes of transmission showed dramatic changes with a 504% increase in sexual transmission of HIV, 90% decrease in blood/plasma transmission, and 35% decrease in injecting drug user transmission. Sexual transmission was the major transmission route among women (44%) and the elderly (59% in men, 44% in women) as well as among permanent (36%) and urban residents (33%). Among those <65 years old, women increased more than men, but among those ≥65 years, men increased more than women. Migrants contributed to the variance of HIV infection between counties but not within counties. The length of highway and urbanization combined with illiteracy were risk factors for HIV/AIDS. Conclusions/Significance Rates of HIV/AIDS among permanent urban residents, particularly women and elderly men, have increased significantly in recent years. To prevent HIV from spreading further among the general population, additional attention should be paid to these populations as well as to migrants.

Prevalence and risk behaviours for Chlamydia trachomatis and Neisseria gonorrhoeae infection among female sex workers in an HIV/AIDS high-risk area

The objectives of this study were to estimate the prevalence of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection among female sex workers (FSWs) in an HIV/AIDS high-risk area in China and to examine risk factors associated with CT or NG infection. A cross-sectional study of 568 FSWs was conducted in Kaiyuan City, Yunnan Province, PR China. The prevalence rates of HIV, CT and NG in the study participants were 11.1%, 17.4% and 8.3%, respectively. More than one-fifth (21.3%) of participants tested positive for either CT or NG. This study identifies a relatively high prevalence of CT or NG infection among FSWs in Kaiyuan. Notably, HIV infection was found to be associated with NG infection and study participants who tested positive for NG had a higher rate of CT infection. Further studies are warranted to examine the prevalence and spread of CT and NG in China, and their potential impact on the HIV epidemic.

Application of the BED capture enzyme immunoassay for HIV incidence estimation among female sex workers in Kaiyuan City, China, 2006–2007

OBJECTIVE To estimate HIV incidence among female sex workers (FSWs) by serial cross-sectional surveys and IgG-capture BED-enzyme immunoassay (BED-CEIA). METHODS We conducted three cross-sectional surveys, 6 months apart, among all consenting FSWs in Kaiyuan City, China. HIV antibody-positive samples were also tested by BED-CEIA. RESULTS Among 1412 unique participants, 475 tested HIV-negative and attended >1 survey (longitudinal cohort). Compared to 786 HIV-negative FSWs who only participated once, the longitudinal cohort reported more illicit drug use (10.9% vs. 7.4%, p=0.03), injected drugs more often in the previous 3 months (8.8% vs. 5.3%, p=0.02), and had more positive urine opiate tests (13.7% vs. 8.9%, p=0.008). Four participants in the longitudinal cohort seroconverted over the year, with an overall incidence of 1.1/100 person-years (95% confidence interval (CI) 0.3-2.8). Crude BED-CEIA incidence was 3.4/100 person-years (95% CI 2.3-4.4) with adjusted rates similar to the cohort incidence: McDougal, 1.5/100 person-years (95% CI 1.0-2.0); Hargrove, 1.6/100 person-years (95% CI 1.1-2.1). The BED-CEIA false-positive rate was 4.4% (10/229) among samples from FSWs known to be infected > or =365 days. CONCLUSIONS Although limited by power, this study provides additional data towards validating BED-CEIA in China. If confirmed by other studies, BED-CEIA will be a useful tool to estimate HIV incidence rates and trends.

HIV incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China.

Background Heterosexual sex is replacing injection drug use as the main mode of HIV transmission in China. The objective of this study is to determine HIV incidence and associated risk factors among female sex workers (FSWs) in China. Methods From March 2006 to November 2009, FSWs in Kaiyuan City, Yunnan were recruited into an open cohort study. Participants were interviewed and tested for HIV and sexually transmitted infections every 6 months. A multivariate Cox proportional hazards regression model with time-dependent variables was used to measure associations between independent variables and HIV seroconversion. Results During 3.5 years of follow-up, 19 incident cases of HIV infection were diagnosed, yielding an overall incidence of 1.44 per 100 person-years (95% confidence interval [CI]: 0.87–2.24). In the multivariate Cox proportional hazards regression model, noninjection drug use (adjusted hazard ratio [AHR]: 6.7, 95% CI: 2.25–19.93), inconsistent condom use with clients in the previous week (AHR: 2.9, 95% CI: 1.03–8.34), and number of clients in the previous week ≥7 (AHR: 4.9, 95% CI: 1.81–13.13) were all independent risk factors for HIV seroconversion. Conclusion These results underscore the urgency for preventive interventions on sexual and drug use behaviors among FSWs, including condom promotion as well as sexually transmitted infection screening and treatment.

HIV-1 and STIs Prevalence and Risk Factors of Miners in Mining Districts of Yunnan, China

Objective:To assess HIV/sexually transmitted infection (STI) prevalence and associated risk factors among miners in Yunnan, China. Methods:A cross-sectional study was conducted among 1798 miners in 2 townships of Gejiu City, Yunnan, from March to May 2006. Standardized interviewer-administered questionnaires were completed and specimens collected for HIV/STI testing. Results:The prevalence of HIV, Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, herpes simplex virus-2, and any STIs among all miners was 0.7%, 4.8%, 0.8%, 1.8%, 9.6%, and 14.9%, respectively. One fifth of miners reported patronizing female sex workers (FSWs) at least once, and of these, 72% never used a condom with a FSW. Miners who visited FSWs had a higher prevalence of HIV (1.8% vs. 0.5%) and any STI (23.2% vs. 4.3%), including C. trachomatis (6.9% vs. 4.3%), N. gonorrhoeae (2.1% vs. 0.5%), and herpes simplex virus-2 (14.9% vs. 8.4%), and higher rates of illegal drug use compared with miners who visited no FSWs. Conclusions:High prevalence of HIV/STIs among miners in Gejiu warrants special attention to this population, and vigorous interventions should address both sexual and drug use-related risk.