Epidemiological Study On HIV / AIDS Among Sex Workers And Clients In Kaiyuan City, Yunnan Province

Background According to the HIV/AIDS reporting system, heterosexual transmission has been the primary mode of HIV transmission in China. The prevalence of HIV was high in female sex workers (FSWs) and their clients, and they play an important role in heterosexual transmission of HIV. Therefore, strengthened understanding of the epidemilogy of HIV among FSWs and their clients will be beneficial to the HIV transmission prevention and control work.Objectives To investigate the incidence and risk factors of HIV infection in FSWs and their clients in Kaiyuan city; to assess the possibility of HIV transmission via unsafe sexual activity from HIV-infected FSWs; to investigate the distribution of HIV genotypes among FSWs and their clients.Methods The Kaiyuan longitudinal study of FSWs is an open cohort study initiated in March 2006, and the longitudinal study of clients of FSWs was initiated in April 2008. The two longitudinal studies were conducted every 6 months by staff members from the China CDC and the Kaiyuan CDC. Univariate and multivariate Cox regression models with time-independent variables were used to investigate the hazard ratios (HR) and 95% confidence interval (CI) of HIV acquisition risk factors. Generalized estimating equations (GEE) approach was used to investigate the risk factor of high viral load in HIV-positive FSWs.Results1. Trends in HIV incidence and risk factors among Kaiyuan FSWs A total of 1184 HIV-1 seronegative FSWs were recruited in our study, among them 33 experienced HIV seroconversions.1184 FSWs contributed a total observation period of 3117.1 person years (PYs), yielding an incidence of HIV infection 1.06 (95%CI: 0.74-1.47) per 100 PYs. The mean duration of follow-up was 2.6 years (S.E. 2.4 years). The cumulative incidence of HIV in FSWs has been decreased from 1.10/100 PYs in 2006-2008 to 1.00/100 PYs in 2012-2014. In multivariate analysis, FSWs who consistent used condom with clients in previous month (adjusted hazard ratio[AHR]=0.29,95%CI:0.13-0.64) had significantly lower risk of becoming infected with HIV, while FSWs who have more than 10 clients per month (AHR=2.44, 95%CI:1.15-5.17) and who were drug users (AHR=3.06,95%CI:1.49-6.30) were more likely to acquire HIV. The proportion of consistent condom use with clients in previous month has been increased from 89.2% in 2006 to 97.7% in 2013, with a slight descrease to 88.7 in 2014. In drug used FSWs, the proportion of injected drugs in past three month has been siginificant descreased from 43.4% to 8.3% and the proportion of shared needles in past three month also descreasd from 6.2% to 0%.2. Trends in HIV incidence and risk factors among clients of FSWs in Kaiyuan A total of 470 HIV-1 seronegative clients of FSWs were recruited in our study, contributed a total observation period of 739.1 PYs, with the mean duration of follow-up was 1.6 years (S.E. 1.5 years). Among them 15 experienced HIV seroconversions, yielding an incidence of 2.03 (95%CI:1.19-3.26) per 100 PYs. The cumulative incidence of HIV in clients of FSWs has been decreased from 2.3/100 PYs in 2008-2010 to 1.78/100 PYs in 2012-2014. In multivariate analysis, clients who consistent used condom with FSWs in past year (AHR=0.27,95%CI:0.08-0.86) had significantly lower risk of becoming infected with HIV, while clients whose HSV-2 status was positive (AHR=2.44,95%CI:1.15-5.17) were more likely to acquire HIV. The proportion of consistent condom use with FSWs in past year has been increased from 49.1 in 2008 to 73.6% in 2013, with a slight descrease in 2014 (69.9%).3. The second transmission of HIV positive FSWs From 2009 to 2014,226 HIV positive FSWs were recruited in our study. Compared with HIV negtivige FSWs, HIV positive FSWs were prone to engage higher risk behavior. In the self-reported HIV positive FSWs, only 12.2% to 41.2% FSWs had done partner notification. The proportion of consistant condom use with partner in last six month was ranged from 33.3% to 85.7%. The mean number of clients in previous month was around 11.2 to 20.3, and the proportion of consistant condom use in previous month was around 86.7% to 95.0%. The incidence of HSV-2 infection was 15.9(95%CI:8.4.0-27.6) per 100 PYs, which was higher than in HIV negative FSWs and the incidence of syphilis infection was 4.0(95%CI:2.4-6.1) per 100 PYs, which was also higher than in HIV negative FSWs. We found that the viral load was higher than 400 copies per ml in 20.0% to 68.3% HIV positive FSWs, indicating a higher risk of HIV transmission to others. In multivariate GEE analysis, we found that diagnoise time, drug use, CD4 count and antiretroviral treatment (ART) had impacted on the HIV viral load in HIV positive FSWs. FSWs who used drug (adjusted odds ratio[AOR]=2.23,95%CI: 1.27-3.91) were significately associated with higher viral load, while FSWs who were diagnoised HIV positive more than 5 years (AOR=0.59,95%CI:0.38-0.92), received ART (AOR=0.13,95%CI:0.08-0.21), and whose CD4 count was higher than 350 cells per mm3 (AOR=0.62,95%CI:0.40-0.96) were associated with lower viral load.4. Distribution of HIV genotype in Kaiyuan From June 2013 to June 2014,HIV positive blood samples were collected from 104 FSWs and 43 clients. Finally,77 persons’ samples were successfully genotyped. The predominant HIV genotypes were CRF08_BC (58.4%) and CRF07_BC (33.8%), and genotypes CRF01_AE and BC were accounting for 5.2%,2.6% respectively.Conclusions High incidence of HIV infection was found in both FSWs and their clients, and slightly decreasing trends were observed. In FSWs, the associated factors for HIV acquisition were consistent used condom with clients in previous month, have more than 10 clients per month and drug users. In clients, the associated factors for HIV acquisition were consistent used condom with FSWs in past year and HSV-2 status. A large proportion of HIV positive females continued engaged commercial sex in Kaiyuan city, and the high incidence of HSV-2 and syphilis as a biomarker indicated ongoing high-risk sexual behavior. Among them the rate of partner notification was low and rarely of them notified their HIV status to clients. So the priority interventions should place on following three groups of people:drug use FSWs, clients of FSWs and HIV positive FSWs.