Short-term toxicity assessment of combined use of zidovudine, lamivudine and lopinavir/ritonavir in vitro and in vivo.

INTRODUCTION: A combination of zidovudine (AZT), lamivudine (3TC) and lopinavir/ritonavir (LPV/r) is one of the most effective drugs for preventing mother-to-child transmission (PMTCT) of HIV. However, limited information is available regarding its systemic toxicity. This study aimed to investigate its potential toxicity. METHOD: An acute oral toxicity test was conducted to assess the potential acute toxicity of AZT + 3TC + LPV/r. Bacterial reverse mutation, mammalian erythrocyte micronucleus and mouse spermatogonia chromosomal aberration tests were conducted to assess its potential genotoxicity. A 28-day feeding test was conducted to assess the potential subacute toxicity. RESULTS: In mice, the LD50 of the AZT + 3TC + LPV/r mixture was greater than 2000 mg/kg body weight (BW). The rate of micronucleated polychromatic erythrocytes (PCEs) increased in a dose-dependent manner in mice (P < 0.01). After treatment with AZT + 3TC + LPV/r for 28 days, the BW gain of male and female rats in the high-dose group was lower than that in the control group (P < 0.05); the relative weights of the liver, kidney, spleen and brain increased (P < 0.05); and pathological abnormalities appeared in the thyroid and spleen of male and female rats in the high-dose group. The haemoglobin (HGB) and red blood cells (RBCs) count in male and female rats decreased, but the white blood cells (WBCs) and lymphocyte apoptosis rates in male and female rats in the high-dose group increased (P < 0.05). The total protein, albumin, cholesterol and blood glucose levels of male and female rats in the high-dose group were significantly decreased (P < 0.05). The alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine (Cr) and blood urea nitrogen (BUN) levels of male and female rats in the medium- and high-dose groups increased significantly (P < 0.05). CONCLUSION: The results suggest that AZT + 3TC + LPV/r may exhibit genotoxicity and subacute toxicity under experimental conditions.

HIV Epidemiology, Care, and Treatment Outcomes Among Student and Nonstudent Youths Living With HIV in Southwest China Between 1996 and 2019: Historical Cohort Study.

BACKGROUND: Nearly one-third of new HIV infections occurred among youth in 2019 worldwide. Previous studies suggested that student youths living with HIV and nonstudent youths living with HIV might differ in some risk factors, transmission routes, HIV care, and disease outcomes. OBJECTIVE: This study aimed to compare the HIV epidemic, disease outcomes, and access to care among student and nonstudent youths living with HIV aged 16 to 25 years in Guangxi, China. METHODS: We performed a historical cohort study by extracting data on all HIV or AIDS cases aged 16 to 25 years in Guangxi, China, during 1996-2019 from the Chinese Comprehensive Response Information Management System of HIV or AIDS. We conducted analyses to assess possible differences in demographic and behavioral characteristics, HIV care, and disease outcomes between student and nonstudent youths living with HIV. Multivariate Cox regression was used to assess differences in mortality and virologic failure between student and nonstudent cases. RESULTS: A total of 13,839 youths aged 16 to 25 years were infected with HIV during 1996-2019. Among them, 10,202 cases were infected through sexual contact, most of whom were men (n=5507, 54%); 868 (8.5%) were students, and 9334 (91.5%) were not students. The number of student youths living with HIV was lower before 2006 but gradually increased from 2007 to 2019. In contrast, the nonstudent cases increased rapidly in 2005, then gradually declined after 2012. Student cases were mainly infected through homosexual contact (n=614, 70.7% vs n=1447, 15.5%; P<.001), while nonstudent cases were more likely to be infected through heterosexual contact (n=7887, 84.5% vs n=254, 29.3%; P<.001). Moreover, nonstudent cases had a significantly lower CD4 count than student cases at the time of HIV diagnosis (332 vs 362 cells/µL; P<.001). Nonstudents also had a delayed antiretroviral therapy (ART) initiation compared to students (93 days vs 22 days; P<.001). Furthermore, the mortality rate of 0.4 and 1.0 deaths per 100 person-years were recorded for student and nonstudent youths with HIV, respectively. Overall, the mortality risk in nonstudent cases was 2.3 times that of student cases (adjusted hazard ratio [AHR] 2.3, 95% CI 1.2-4.2; P=.008). The virologic failure rate was 2.3 and 2.6 per 100 person-years among student and nonstudent youths living with HIV, respectively. Nonstudent cases had double the risk of virologic failure compared to student cases (AHR 1.9, 95% CI 1.3-2.6; P<.001). CONCLUSIONS: Nonstudent youths living with HIV might face a low CD4 count at the time of HIV diagnosis, delayed ART initiation, and increased risk of death and virologic failure. Thus, HIV prevention and interventions should target youths who dropped out of school early to encourage safe sex and HIV screening, remove barriers to HIV care, and promote early ART initiation to curb the HIV epidemic among youths.

Genetic network analysis of human immunodeficiency virus sexual transmission in rural Southwest China after the expansion of antiretroviral therapy: A population-based study.

Background: This study is used to analyze the genetic network of HIV sexual transmission in rural areas of Southwest China after expanding antiretroviral therapy (ART) and to investigate the factors associated with HIV sexual transmission through the genetic network. Materials and methods: This was a longitudinal genetic network study in Guangxi, China. The baseline survey and follow-up study were conducted among patients with HIV in 2015, and among those newly diagnosed from 2016 to 2018, respectively. A generalized estimating equation model was employed to explore the factors associated with HIV transmission through the genetic linkage between newly diagnosed patients with HIV (2016-2018) and those at baseline (2015-2017), respectively. Results: Of 3,259 identified HIV patient sequences, 2,714 patients were at baseline, and 545 were newly diagnosed patients with HIV at follow-up. A total of 8,691 baseline objectives were observed by repeated measurement analysis. The prevention efficacy in HIV transmission for treated HIV patients was 33% [adjusted odds ratio (AOR): 0.67, 95% confidence interval (CI): 0.48-0.93]. Stratified analyses indicated the prevention efficacy in HIV transmission for treated HIV patients with a viral load (VL) of <50 copies/ml and those treated for 4 years with a VL of <50 copies/ml to be 41 [AOR: 0.59, 95% CI: 0.43-0.82] and 65% [AOR: 0.35, 95% CI: 0.24-0.50], respectively. No significant reduction in HIV transmission occurred among treated HIV patients with VL missing or treated HIV patients on dropout. Some factors were associated with HIV transmission, including over 50 years old, men, Zhuang and other nationalities, with less than secondary schooling, working as a farmer, and heterosexual transmission. Conclusion: This study reveals the role of ART in reducing HIV transmission, and those older male farmers with less than secondary schooling are at high risk of HIV infection at a population level. Improvements to ART efficacy for patients with HIV and precision intervention on high-risk individuals during the expansion of ART are urgently required.

Survey of pretreatment HIV drug resistance and the genetic transmission networks among HIV-positive individuals in southwestern China, 2014-2020.

BACKGROUND: Pretreatment drug resistance (PDR) can limit the effectiveness of HIV antiretroviral therapy (ART). The aim of this study was to assess the prevalence of PDR among HIV-positive individuals that initiated antiretroviral therapy in 2014-2020 in southwestern China. METHODS: Consecutive cross-sectional surveys were conducted in Qinzhou, Guangxi. We obtained blood samples from individuals who were newly diagnosed with HIV in 2014-2020. PDR and genetic networks analyses were performed by HIV-1 pol sequences using the Stanford HIV-database algorithm and HIV-TRACE, respectively. Univariate and multivariate logistic regression models were used to explore the potential factors associated with PDR. RESULTS: In total, 3236 eligible HIV-positive individuals were included. The overall prevalence of PDR was 6.0% (194/3236). The PDR frequency to NNRTI (3.3%) was much higher than that of NRTI (1.7%, p < 0.001) and PI (1.2%, p < 0.001). A multivariate logistic regression analysis revealed that PDR was significantly higher among individuals aged 18-29 (adjusted odds ratio (aOR): 1.79, 95% CI 1.28-2.50) or 30-49 (aOR: 2.82, 95% CI 1.73-4.82), and harboring CRF08_BC (aOR: 3.23, 95% CI 1.58-6.59). A total of 1429 (43.8%) sequences were linked forming transmission clusters ranging in size from 2 to 119 individuals. Twenty-two individuals in 10 clusters had the same drug resistant mutations (DRMs), mostly to NNRTIs (50%, 5/10). CONCLUSIONS: The overall prevalence of PDR was medium, numerous cases of the same DRMs among genetically linked individuals in networks further illustrated the importance of surveillance studies for mitigating PDR.

[Effects of Human Immunodeficiency Virus-positive Mothers Receiving Antiretroviral Therapy to Prevent Mother-to-child Transmission on the Growth and Development of 18-month-old Children in Lingshan County of Guangxi].

Objective To evaluate the effects of antiretroviral therapy(ART)for the prevention of mother-to-child transmission(PMTCT)of acquired immune deficiency syndrome(AIDS)on the growth and development of 18-month-old children born by human immunodeficiency virus(HIV)-positive pregnant women in Lingshan County,Guangxi Zhuang Autonomous Region,and provide scientific evidence for improving the ART medication plan for PMTCT.Methods Lingshan County,ranking the first in the HIV-epidemic counties of Guangxi,was selected as the research site.According to the design of retrospective case-control study,we assigned all the subjects into the case group and the control group:(1)The case group included the HIV-positive pregnant women who had received ART for PMTCT and their HIV-negative infants in Lingshan County from 2010 to 2017.The historical cards and PMTCT data of them were collected from the national PMTCT database.(2)The control group included the healthy pregnant women and their healthy babies born in the Lingshan Maternity and Infant Hospital in 2017,and the children's growth and development data were collected.The stunted growth in children was defined as at least one of the three main indicators of body height,body weight,and head circumference below the normal range.Results The number of HIV-positive mothers and their infants in the case group was 391 and 368,respectively,and 87.21%(341/391)and 95.38%(351/368)of mothers and infants respectively received ART medication.The HIV positive rate,mortality rate,and mother-to-child transmission rate of 18-month-old children were 1.36%(5/368),4.35%(16/368),and 2.01%(5/249),respectively.The incidence of stunted growth of 18-month-old children in the case group and the control group was 42.12%(155/368)and 23.06%(101/438),respectively,with significant difference(χ2=33.520,P<0.001).Conclusion After HIV-positive mothers in Lingshan County of Guangxi received ART for PMTCT,the incidence of growth stunting in 18-month-old children increased.

Using longitudinal genetic-network study to understand HIV treatment-as-prevention.

OBJECTIVE: The WHO has recommended that antiretroviral therapy be provided to all HIV patients to reduce future HIV transmission rates. However, few studies have examined this public health strategy at the population level in a real-world setting. METHODS: In this longitudinal genetic-network study in Guangxi, China, the baseline and follow-up data were collected from HIV patients in 2014 and newly diagnosed HIV patients from 2015 to 2018, respectively. The prevention efficacy was used to estimate the effect of treatment-as-prevention in reducing HIV secondary transmission. RESULTS: Among 804 newly diagnosed HIV patients during 2015-2018, 399 (49.6%) of them genetically linked to HIV patients at baseline during 2014-2017. The overall proportion of genetic linkage between newly diagnosed HIV patients during 2015-2018 with untreated and treated HIV patients at baseline during 2014-2017 was 6.2 and 2.9%, respectively. The prevention efficacy in HIV transmission for treated HIV patients was 53.6% [95% confidence interval (95% CI): 42.1-65.1]. Subgroup analyses indicated an 80.3% (95% CI: 74.8-85.8) reduction in HIV transmission among HIV patients who were treated for 4 years or more and had viral loads less than 50 copies/ml. There was no significant reduction in HIV transmission among treated HIV patients who dropped out or who had missing viral load measures. CONCLUSION: Our study results support the feasibility of treating all HIV patients for future reductions in HIV transmission at the population level in real-world settings. Comprehensive intervention prevention programmes are urgently needed.

Optimal transportation planning of classified domestic garbage based on map distance.

Domestic garbage classification is required in many cities, however, optimal transportation of classified garbage has not been widely studied. Here, the optimal transportation of the classified domestic garbage from the waste transfer center to the garbage disposal station is considered. The locations of waste transfer centers, map distances between these waste transfer centers, different types of garbage disposal stations and the quantity of waste in different areas are used as key factors for constructing a weighted graph model. This study considers Nanshan District in Shenzhen, China as a case study. Solutions were obtained by applying the proposed model to the area using data from 2011. To achieve the decision goal of identifying feasible traveling distance and time for each trash truck, the number of routes considered for recyclable waste transportation was no less than 5; for non-recyclable waste transportation was no less than 2; and for harmful waste transportation was 4. The study provides an auxiliary management tool for optimal municipal solid waste disposal that improves the sustainability of the system.

HIV Epidemiology and Prevention in Southwestern China: Trends from 1996-2017.

The aim of this review is to describe long-term HIV epidemiology and prevention trends in Guangxi, a provincial-level region located along a major drug trafficking corridor in southwestern China. Between 1996 and 2006, HIV transmission in Guangxi was primarily fueled by Injection Drug Use (IDU). Since 2006, heterosexual sex has become the dominant mode of HIV transmission, followed by drug injection. Moreover, older, heterosexual adults appear to be at increased risk for HIV. The vast majority of new HIV cases are attributed to local HIV subtypes already circulating within Guangxi (93%), though imported subtypes are associated with younger age groups. Since 2011, HIV incidence in Guangxi has stabilized, due in part to HIV prevention efforts that include expanded HIV testing, antiretroviral treatment, and other intervention measures. Between 1996 and 2017, Guangxi, China experienced dramatic changes in the primary HIV transmission mode and at-risk age group. Due in part to local and National AIDS control and prevention campaigns, HIV incidence trends in Guangxi no longer appear to be increasing.

Treatment outcomes of initial differential antiretroviral regimens among HIV patients in Southwest China: comparison from an observational cohort study.

OBJECTIVES: China has continued to expand antiretroviral therapy (ART) services and optimise ART guidelines in an effort to significantly reduce and prevent mortality and transmission rates among HIV patients. However, no study to date has compared treatment outcomes of initial differential antiretroviral regimens among HIV patients in a real-world setting in China. This study aimed to compare the effects of different ART regimens on treatment outcomes among adults. DESIGN: Observational retrospective cohort study. SETTING: Data from 2011 to 2013 in Guangxi, China. PARTICIPANTS: Patients aged ≥18 years (n=25 732) were selected. RESULTS: A total of 25 732 patients were included in this study. The average mortality and attrition rate were 2.64 and 4.98, respectively, per 100 person-years. Using Cox proportional hazard models, zidovudine-based (AZT-based) regimen versus stavudine-based (D4T-based) regimen had an adjusted HR (AHR) for death of 0.65 (95% CI 0.58 to 0.73); the AHR of tenofovir-based (TDF-based) versus D4T-based regimens was 0.81 (95% CI 0.71 to 0.92), and of lopinavir-ritonavir-based (LPV/r-based) versus D4T-based regimens, 1.19 (95% CI 1.04 to 1.37). AZT-based versus D4T-based regimens had an AHR for dropout of 0.89 (95% CI 0.81 to 0.97); this ratio for TDF-based versus D4T-based regimens was 0.88 (95% CI 0.80 to 0.98), and for LPV/r-based versus D4T-based regimens, 1.42 (95% CI 1.27 to 1.58). AZT-based and TDF-based regimens had a lower risk compared with D4T-based regimens, while LPV/r-based regimens had a higher risk. High gastrointestinal reactions and poor adherence were observed among HIV patients whose initial ART regimen was LPV/r-based. CONCLUSIONS: Our study found that the treatment outcomes of initial ART regimens that were AZT-based or TDF-based were significantly better than D4T-based or LPV/r-based regimens. This finding could be related to the higher rates of gastrointestinal reactions and poorer adherence associated with the LPV/r-based regimens compared with other initial ART regimens.

Treatment for HIV prevention study in southwestern areas of China.

BACKGROUND: China has ambitious to achieve significant reductions in HIV transmission and HIV-related mortality by adopting the World Health Organization's "Treat All" approach. Such a prevention strategy is needed future study on regional scale. METHODS: An observational cohort study of HIV epidemiology and treatment databases was used to study the effectiveness of antiretroviral therapy on the transmission of HIV in serodiscordant couples in Guangxi of China. RESULTS: A total of 7713 couples were entered into the cohort study analysis which included 1885 couples in the treatment-naive cohort and 5828 couples in the treated cohort. During the follow-up of 18985.29 person-years from 2003 to 2014, the average incidence of HIV was 2.4 per 100 person-years (95% CI 2.1-2.6). HIV seroincidence rate was significantly higher among the treatment naive group (4.2 per 100 person-years, 3.7-4.8) compared with the on treatment group (1.6 per 100 person-years, 1.3-1.8). An overall 45% reduction in risk of HIV transmission among serodiscordant couple was associated with ART treatment (adjusted Hazard Ratio [HR] 0.55, 95% Confidence Interval [CI] 0.44-0.69). Treatment prevention had significantly effectiveness for most baseline characteristics of index partners, such as for male, female, age above 25 years, education below high school, farmer, infected by heterosexual intercourse. CONCLUSION: Treatment-as-prevention can be implemented in the real-world on a national or regional scale, but ART adherence and comprehensive harm reduction while implementing this strategy require further study.

Patient characteristics and perceived health status of individuals with HIV and tuberculosis coinfection in Guangxi, China.

To explore demographics, clinical and medication profiles, patients' social support, and perceived health status in HIV/TB coinfected patients in Guangxi, China.We performed a cross-sectional study in the HIV clinic of the Guigang City People's Hospital (N = 150). Health professionals conducted face-to-face interviews and collected data from patients' electronic medical records regarding patients' demographic, clinical, and medication information, as well as their social support and perceived health status. We classified all HIV/AIDS patients into HIV monoinfected and TB coinfected, at a ratio of 2:1.Compared with the HIV monoinfected, patients with HIV/TB coinfection were more likely to be older, male, less educated, unemployed, carrying health insurance, having advanced stage of HIV infection, longer history with HIV, and other opportunistic infections. Patients coinfected with TB were also more likely to hold a negative belief that their HIV treatment could prevent exacerbations, and reported significantly worse emotional/informational support, social interaction, and perceived health status. Better social support and better self-efficacy to the HIV treatment adherence was significantly associated with better perceived health status among patients with HIV and TB coinfection.Having HIV/TB coinfection was associated with poorer perceived general well-being and mental health, particularly in those undergoing TB therapy. Our findings suggest the need for mental health referrals and medication management for coinfected individuals, as well as further efforts and policies to improve coordinated care.

[Cost-effectiveness of the HIV screening program carried out in Guangxi Zhuang Autonomous Region infectious disease special demonstration project areas].

OBJECTIVE: To analyze the cost effectiveness of HIV screening project in three Guangxi infectious disease special demonstration project countries in 2013. METHODS: To calculate the funds used for the HIV screening project and to study the data on HIV/AIDS and HAART. A five-tree markov model was used to evaluate the quality adjusted life year (QALY) of this HIV screening project and to analyze the related cost effectiveness of the project. RESULTS: The cost of HIV screening in Guangxi infectious disease special demonstration project areas was 19.205 million Yuan and having identified 1 218 HIV/AIDS patients. The average costs for HIV/AIDS positive detection in three project countries were 14.562, 18.424 and 14.042 thousand Yuan per case. The QALYs gained from finding a HIV/AIDS case were 12.736, 8.523 and 8.321 on average, with the total number of QALYs gained from the project as 5 973.184, 3 613.752 and 2 704.325. The overall cost effectiveness ratio of the project was 1.562 thousand Yuan per QALY, and 1.143, 2.162 and 1.688 thousand Yuan per QALY in these three project countries. Project country "A" showed better cost effectiveness index than country B and C. CONCLUSION: The HIV screening project in Guangxi seemed relatively cost-effective but the average cost of HIV/AIDS positive detection was expensive. To strengthen HAART work for HIV/AIDS could improve the cost-effective of the project.

[Study on the characteristics of commercial sexual behavior and the risk factors analysis of HIV infection among the old male clients, in Guangxi].

OBJECTIVE: To understand the current situation and characteristics of commercial sexual behavior among old male clients in Guangxi, and to explore the associated risk factors of HIV infection. METHODS: The areas in Guangxi where more old male HIV cases were reported followed by survey on those male clients who were over 60 years of age, were selected. A total of 5 ml blood sample was collected to test antibodies of HIV and syphilis. Risk factors were calculated by the multivariate logistic analysis method. RESULTS: A total of 1 236 questionnaires were completed in the survey. 65.61% of the old male clients were from low-grade venues with 53.64% of them never using a condom when engaging in commercial sex behavior. 47.33% of them patronized sex workers for around 10 years. 53.32% of them patronized prostitutes not less than 2 times in the last 30 days. Thirty subjects were HIV positive (2.43%) and 40 were syphilis positive (3.24%). Factor as 'having fixed partners' (OR = 0.302, 95% CI:0.140-0.650) appeared protective for the old male clients of HIV infection, with a history of patronizing sex workers from 1 to 5 years (OR = 2.552, 95% CI: 1.086-5.998). Frequency of patronizing sex workers not less than 4 times in the last 30 days (OR = 3.002, 95%CI:1.047-8.607) seemed the high risk factor of HIV infection. CONCLUSION: Older-aged male clients showed high HIV and syphilis infection rates in Guangxi, and most of them were using the low-grade venues. Commercial sexual behaviors in the areas would include early and, frequent exposure, but with poor protections. High risk factors of HIV infection might relate to "no fixed sexual partners" and "frequently commercial sexual behavior".

[Demographic characteristics HIV positive cases aged no less than 15 years old and related factors in communicable disease prevention demonstration area in Guangxi Zhuang autonomous region].

OBJECTIVE: To understand the demographic characteristics of the HIV positive cases detected in the screening project in communicable disease prevention demonstration area in Guangxi Zhuang autonomous region and analyses the related factors of HIV infection. METHODS: HIV antibody detection was conducted for local people aged no less than 15 years old in 3 demonstration counties, and the demographic information of the subjects were collected. The factors influencing HIV infection were analyzed with software PASW Statistics 18.0. RESULTS: A total of 770 454 local people aged over 15 years were screened, the HIV infection rate was 1.58‰ among them. The positive cases were mainly married males aged≥30 years and with the educational level of primary school and junior middle school. Thus male, age over 30 years and educational level of primary school and junior middle school. were the common risk factors for HIV infection, whereas being married was a protective factor for HIV infection in 3 demonstration counties, but Han ethnic group and divorced/widowed were risk factors for HIV infection in the demonstration county A, non-farmer, divorced/widowed and educational level of senior middle school were the risk factors for HIV infection in demonstration county B and Han ethnic group and farmer were risk factors HIV infection in demonstration county C. CONCLUSION: It suggested to conduct targeted HIV infection screening according to the survey results to find out the HIV cases in general population.

[Sildenafil use and relevant risk factors among middle-aged or elderly male clients of female commercial sex workers in the central areas of Guangxi, China].

OBJECTIVE: To understand the illegal sidenafil use among middle-aged and elderly male clients of female sex workers (FSWs) in central region of Guangxi as well as on related risk factors. Initial evaluation regarding the effect of illegal sidenafil use on HIV infection among the middle-aged and elderly men was also conducted. METHODS: A survey was conducted among the over 50-year-olds male clients of low-grade prostitutions in central areas of Guangxi. Information on demographics, related behavior, and illegal sidenafil use was collected. 5 ml blood sample were taken to test antibodies of HIV and syphilis. PASW Statistics 18.0 was used for data analysis. RESULTS: 2 056 questionnaires were completed. 23.1% of the participants said they had ever used illegal sidenafil. The risk of sildenafil use was low among the male clients who were not over 60 years old (OR = 0.586, 95% CI:0.459-0.749). The risks of sildenafil use among the male clients with frequencies(in the past 30 days) of having commercial sex behavior were:only once (OR = 0.184, 95%CI:0.090- 0.378), twice (OR = 0.187, 95%CI:0.089-0.378) or three times (OR = 0.181, 95%CI: 0.085-0.384) lower than those with more than five times. Being single (OR = 0.608, 95% CI: 0.396-0.933), married/cohabiting (OR = 0.533, 95% CI:0.391-0.727), having unstable partners (OR = 0.558, 95%CI:0.393-0.792) seemed to be protective on those who used sildenafil, among the study population. Factors as 'never use the condom (OR = 1.642, 95%CI:1.125-2.397) or 'seldom use as condom (OR = 1.840, 95%CI:1.278-2.648) when having commercial sex, were under high risk among the sildenafil users. Forty-seven subjects were HIV positive, with the prevalence as 2.29% in this study population. Male clients of the FSWs who used sidenafil were under 60 years of age and with higher risk of HIV infection. CONCLUSION: people who were ≥60 years old, divorced/widowed/ separated, with frequencies (in the past 30 days) of having commercial sex more than 5 times, never or occasionally using a condom when having commercial sex etc., appeared at high risk. Middle-aged and elderly male clients who used sildenafil or sildenafil-like drugs were under high risk of contracting HIV infection.