An evaluation of assumptions underlying respondent-driven sampling and the social contexts of sexual and gender minority youth participating in HIV clinical trials in the United States.

INTRODUCTION: Respondent-driven sampling has been an effective sampling strategy for HIV research in many settings, but has had limited success among some youth in the United States. We evaluated a modified RDS approach for sampling Black and Latinx sexual and gender minority youth (BLSGMY) and evaluates how lived experiences and social contexts of BLSGMY youth may impact traditional RDS assumptions. METHODS: RDS was implemented in three cities to engage BLSGMY in HIV prevention or care intervention trials. RDS was modified to include targeted seed recruitment from venues, internet, and health clinics, and provided options for electronic or paper coupons. Qualitative interviews were conducted among a sub-sample of RDS participants to explore their experiences with RDS. Interviews were coded using RDS assumptions as an analytic framework. RESULTS: Between August 2017 and October 2019, 405 participants were enrolled, 1,670 coupons were distributed, with 133 returned, yielding a 0.079 return rate. The maximum recruitment depth was 4 waves among seeds that propagated. Self-reported median network size was 5 (IQR 2-10) and reduced to 3 (IQR 1-5) when asked how many peers were seen in the past 30 days. Qualitative interviews (n=27) revealed that small social networks, peer trust, and targeted referral of peers with certain characteristics challenged network, random recruitment, and reciprocity assumptions of RDS. HIV stigma and research hesitancy were barriers to participation and peer referral. CONCLUSIONS: Small social networks and varying relationships with peers among BLSGMY challenge assumptions that underlie traditional RDS. Modified RDS approaches, including those that incorporate social media, may support recruitment for community-based research but may challenge assumptions of reciprocal relationships. Research hesitancy and situational barriers must be addressed in recruitment and study designs.

The HIV care continuum among men who have sex with men in Moscow, Russia: a cross-sectional study of infection awareness and engagement in care.

OBJECTIVES: Early diagnosis and treatment of HIV infection is critical to improving clinical outcomes for HIV-infected individuals. We sought to characterise the HIV care continuum and identify correlates of being unaware of one's HIV infection among men who have sex with men (MSM) in Moscow, Russia. METHODS: Participants (N=1376) were recruited via respondent-driven sampling and completed a sociobehavioural survey and HIV testing from 2010 to 2013. Sample and population estimates were calculated for key steps along the HIV care continuum for HIV-infected MSM and logistic regression methods were used to examine correlates of being unaware of one's HIV infection. RESULTS: 15.6% (184/1177; population estimate: 11.6%; 95% CI 8.5% to 14.7%) of participants were HIV infected. Of these, only 23.4% (43/184; population estimate: 13.2; 95% CI 11.0 to 15.4) were previously aware of their infection, 8.7% (16/184 population estimate: 4.7; 95% CI 1.0 to 8.5) were on antiretroviral therapy (ART), and 4.4% (8/164; population estimate: 3.0; 95% CI 0.3 to 5.6) reported an undetectable viral load. Bisexual identity (reference: homosexual; adjusted odds ratio (AOR): 3.69; 95% CI 1.19 to 11.43), having ≥5 sexual partners in the last 6 months (reference: ≤1; AOR: 4.23; 95% CI 1.17 to 15.28), and employer HIV testing requirements (reference: no; AOR: 15.43; 95% CI 1.62 to 147.01) were associated with being unaware of one's HIV infection. HIV testing in a specialised facility (reference: private; AOR: 0.06; 95% CI 0.01 to 0.53) and testing ≥2 times in the last 12 months (reference: none; AOR: 0.17; 95% CI 0.04 to 0.73) were inversely associated with being unaware of HIV infection. CONCLUSIONS: There is a steep gradient along the HIV care continuum for Moscow-based MSM beginning with low awareness of HIV infection. Efforts that improve access to acceptable HIV testing strategies, such as alternative testing facilities, and linkage to care are needed for key populations.

Alcohol Use and Associated Sexual and Substance Use Behaviors Among Men Who Have Sex with Men in Moscow, Russia.

Alcohol use is a public health problem in the Russian Federation. This study explored relationships between alcohol use and behavioral risks for HIV transmission among men who have sex with men (MSM) in Moscow, Russia. Alcohol use disorder identification test (AUDIT) scores for 1367 MSM participating in a cross-sectional survey and HIV testing were categorized to: "abstinence/low use", "hazardous use", "harmful use/dependency". Multiple logistic regression models compared dependent variables for sexual and drug use behaviors across alcohol use strata. Hazardous and harmful/dependent alcohol use were significantly associated with high-risk sexual behaviors and drug use. Harmful use/dependency was associated with an increased odds of having more than five male sex partners (last 12 months; adjusted odds ratios-AOR 1.69; 95 % CI 1.25-2.27), inconsistent condom use during anal intercourse (AOR 2.19; 95 % CI 1.61-2.96) and, among those using recreational drugs, injection drug use (last month; AOR 4.38: 95 % CI 1.13-17.07) compared to abstinent/low-level users. Harmful/dependent use was marginally associated with HIV infection (AOR 1.48; 95 % CI 0.97-2.25). HIV prevention efforts for MSM in Moscow may benefit from addressing problem alcohol use to mitigate high-risk behaviors.

Anal human papillomavirus and HIV: A cross-sectional study among men who have sex with men in Moscow, Russia, 2012-2013.

Anal human papillomavirus (HPV) is prevalent among men who have sex with men (MSM), but has not been studied in the Russian Federation. A cross-sectional survey and HPV genotyping were conducted among HIV seropositive (n=58) and seronegative MSM (n=65)in Moscow. Multivariable logistic regression was performed to identify correlates of infection with oncogenic HPV genotypes 16 and/or 18 (HPV 16/18). Forty per cent (49/124) of all MSM were infected with at least one anal HPV genotype, 31.5% (39/124) had HPV16/18,and 11.5% (14/121) had high-grade squamous intraepithelial lesions (HSIL). HPV 16/18 was more prevalent in HIV seropositive than seronegative men (24/58,41.4% vs 15/65, 23.1%; p=0.03). HIV infection was independently associated with HPV 16/18 (adjusted odds ratio (AOR): 5.08; 95% confidence intervals (CI):1.49-17.34, p=0.01), as was having 2-4 steady male sex partners in the last year (vs ≤ 1 partner; AOR: 6.99;95%CI: 1.94­25.24, p<0.01). History of prison/detention,migration to/within Russia and use of incompatible lubricants were marginally associated with HPV16/18 (p<0.10). Comprehensive prevention options are needed to address HIV and HPV infection among MSM in Russia and may benefit from inclusion of young men in piloted HPV vaccination programmes.

Social and structural risks for HIV among migrant and immigrant men who have sex with men in Moscow, Russia: implications for prevention.

Moscow has a large population of immigrants and migrants from across the Former Soviet Union. Little is studied about men who have sex with men (MSM) within these groups. Qualitative research methods were used to explore identities, practices, and factors affecting HIV prevention and risks among immigrant/migrant MSM in Moscow. Nine interviews and three focus group discussions were conducted between April-June 2010 with immigrant/migrant MSM, analyzed as a subset of a larger population of MSM who participated in qualitative research (n=121). Participants were purposively selected men who reported same sex practices (last 12 months). Migrants were men residing in Moscow but from other Russian regions and immigrants from countries outside of Russia. A socioecological framework was used to describe distal to proximal factors that influenced risks for HIV acquisition. MSM ranged from heterosexual to gay-identified. Stigma and violence related to homophobia in homelands and concerns about xenophobia and distrust of migrants in Moscow were emerged as key themes. Participants reported greater sexual freedom in Moscow but feared relatives in homelands would learn of behaviors in Moscow, often avoiding members of their own ethnicity in Moscow. Internalized homophobia was prevalent and linked to traditional sexual views. Sexual risks included sex work, high numbers of partners, and inconsistent condom use. Avoidance of HIV testing or purchasing false results was related to reporting requirements in Russia, which may bar entry or expel those testing positive. HIV prevention for MSM should consider immigrant/migrant populations, the range of sexual identities, and risk factors among these men. The willingness of some men to socialize with immigrants/migrants of other countries may provide opportunities for peer-based prevention approaches. Immigrants/migrants comprised important proportions of the MSM population, yet are rarely acknowledged in research. Understanding their risks and how to reach them may improve the overall impact of prevention for MSM and adults in Russia.

Modelling the impact of HIV prevention and treatment for men who have sex with men on HIV epidemic trajectories in low- and middle-income countries.

Little is known about the impact of combination HIV prevention interventions for men who have sex with men (MSM) and the impacts on the wider epidemics. Modelling analyses of MSM-specific interventions across varied HIV epidemics may inform evidence-based responses. The Goals model was adapted to project the impacts of providing HIV interventions for MSM and access to expanded coverage of antiretroviral therapy (ART) for adults to measure the effects on the MSM and adult epidemics in Peru, Ukraine, Kenya and Thailand. Positive impacts were observed in all four countries. Across epidemics, 14-25% of infections among MSM may be averted between 2012 and 2016 when MSM interventions are brought to scale and MSM have equal access to expanded ART for adults. Among adults, MSM interventions may avert up to 4000 new infections, in addition to the benefits associated with increased ART. Greatest impacts from expanded interventions were observed in countries where same sex transmission contributes significantly to the HIV epidemic. While significant benefits are observed among the adult and MSM populations with expansion of ART, consideration should be given to the synergies of combining ART expansion with targeted interventions to reach hidden, high-risk populations for HIV testing and counselling and linkages to care.

Social environment and HIV risk among MSM in Hanoi and Thai Nguyen.

Little is known about the effect of the social environment on HIV risk in gay men in northern Vietnam, particularly in rural areas. This qualitative research study conducted 4 key informant interviews and 30 in-depth interviews of men in two northern Vietnamese cities: Hanoi, a large city, and Thai Nguyen, a smaller town. Hanoi has experienced a growth in the number of places where gay men can socialize, access HIV prevention services, and discuss health issues. Thai Nguyen lacks these open venues. However, homosexuality is still highly stigmatized in the general population in both cities. This stigma affects the number of partners and level of sexual risk of participants. Also, men generally reported little communication between partners about sexual risk. While stigma in the general community is difficult to change, social environments where gay men can openly communicate creates an opportunity for HIV prevention and social support.

Assessing the Effects of Anti-Homosexuality Legislation in Uganda on HIV Prevention; Treatment; and Care Services

Uganda's response to the HIV epidemic has been lauded for its robustness and achievements. However; a key component of HIV prevention programming has been missing; for men who have sex with men (MSM). The main reason cited has been criminalization of male homosexual behavior. In 2009; the Anti-Homosexuality Bill (AHB) was introduced in the parliament to enhance existing anti-homosexuality law. A multi-disciplinary team made a Health Impact Assessment of the proposed AHB. The bill as tabled would severely increase punishments; increased closeting. Social capital of MSM would be eroded by clauses mandating reporting by friends; relatives; and acquaintances. Health-care professionals would have to inform on homosexuals. Mandatory HIV testing would be a blow to programming. Probable disclosure of HIV status in a public space (court) would also be a deterrent. Heftier punishments for those testing positive increases stigma and hobbles subsequent care. The AHB argues for exclusion; and more discrimination targeting persons living with HIV and sexual minorities. It will exacerbate the negative public health consequences of the existing legislation. The government of Uganda should review guidance documents published by authoritative bodies including the World Bank; World Health Organization to develop and bring to scale Human rightsaffirming HIV prevention; treatment; and care responses

Quantitative and qualitative correlates of cervicovaginal herpes simplex virus type 2 shedding among HIV-infected women in the Women's Interagency HIV Study.

We identified demographic, clinical and biological determinants of herpes simplex virus type 2 (HSV-2) shedding among HIV-infected participants in the Women's HIV Interagency Study (WIHS). Cervicovaginal lavage (CVL) specimens from 369 HIV-infected HSV seropositive women were tested with TaqMan polymerase chain reaction (PRC) for detection HSV-2 DNA. Seven percent of women tested positive for HSV-2 DNA in CVL. Significant correlates of the presence of HSV-2 DNA in CVL were being younger, African American or Hispanic race/ethnicity and injecting drugs in the past six months (P < 0.05). A borderline significant trend for reduced viral shedding with higher CD4+ T cell counts was observed (P = 0.08). All women who were never observed with any genital lesions and had consistently negative self-reported history of genital sores throughout the follow-up (n = 29, 8%) were negative for CVL HSV-2 DNA. HSV-2 DNA quantity was significantly associated with having frequent subsequent lesion recurrences (Spearman rho = 0.48, P = 0.016; adjusted prevalence ratio [APR] = 2.5, P = 0.012). Increasing the age of the host was inversely correlated with decreased viral shedding over time. However, a subset of older women continued to shed significant amounts of virus despite passage of time. This study provides genital HSV-2 DNA titre as a quantitative and symptom- and sign-based measures as qualitative predictors of HSV-2 shedding from the lower genital tract among HIV-infected women.

Socio-demographic and drug use factors associated with HIV-1 recombinants and dual infections in Northern Thai drug users: associations of risk with genetic complexity.

BACKGROUND: Dual infection with diverse HIV strains can foster the emergence of recombinants. The resulting increase in viral genetic diversity is a major challenge for vaccine development HIV treatment. In this study we aim to investigate the socio demographic factors associated with an increasing level of genetic diversity among HIV strains in a population of drug-users in Northern Thailand. METHODS: From 1999 through 2000, 2231 volunteers were enrolled in the Opiate-Users Research in Chiang Mai, Thailand. HIV subtype analysis was conducted among those HIV-1 seropositive (n=347) using a multi-region hybridization assay. Social and demographic variables were assessed using a structured questionnaire. RESULTS: Overall, 336/347 (96.8%) of the samples could be typed. 81.8% were CRF01_AE, 3.9% were subtype B, 9.2% were recombinants (mostly between CRF01_AE and B) and 5.1% were dual infections. Dual infections were more frequent among those with a lower education level (AOR: 5.2; 95% CI 1.4-20.3), those who have initiated injecting in the last 3 years (AOR: 3.9; 95% CI 1.1-14.6), and those reporting frequent needle sharing in the last 3 months (AOR: 7.0; 95% CI 1.5-34.1). Both recombinant strains and dual infection were more frequent among those reporting frequent needle sharing in the last 3 months (AOR: 5.3; 95% CI 1.6-17.1). CONCLUSION: To limit the expanding complexity of HIV-1 strains, early intervention should be aimed at reduction in needle sharing, especially among new intravenous drug users.

Comparison of methods to detect recent HIV type 1 infection in cross-sectionally collected specimens from a cohort of female sex workers in the Dominican Republic.

Interest in estimating HIV-1 incidence using specimens obtained as part of cross-sectional surveys has led to the development of new methods to detect recent HIV-1 infection through the testing of a single anti-HIV-positive specimen. These assays are based on quantitative and qualitative differences in anti-HIV-1 antibodies between recent and long-standing infections. An ongoing vaccine preparedness study enrolled female sex workers in the Dominican Republic. Specimens from women found to be HIV positive at baseline were tested for recent HIV-1 infection using the detuned assay, avidity index, and BED-CEIA assay. An unweighted kappa statistic in pairwise comparisons was used to estimate the correlation of recent HIV-1 infection detection by the three methods. Nineteen (3.9%) of 482 women were positive for HIV-1 infection. The incidence of HIV infection was 1.4% [95% confidence interval (CI): 0.2, 5.3], 0.9%(95% CI: 0.1, 4.4), and 1.0%(95% CI: 0.1, 4.4) using detuned assay, avidity index, and BED-CEIA techniques, respectively. The overall agreement between both detuned assay and avidity index and detuned assay and BED-CEIA was 94%(kappa = 0.8, 95% CI; 0.3, 1.0). The correlation was highest between BED-CEIA and avidity index methods (100%; kappa = 1.0). All three methods performed similarly in detecting recent HIV-1 infection in this region dominated by clade B HIV-1 infection. Although incidence estimates were slightly higher using the detuned assay method, they were not significantly different. These assays may be of value in both clinical research and practice. The utility of individual assays for recent infection detection will depend upon operating characteristics, HIV-1 subtype limitations, and selection of appropriate assay cutoff values.

Injection prevalence and risks among male ethnic minority drug users in Northern Thailand.

Thailand's rate of HIV due to drug use is increasing, and nearly one-half of clients at a drug treatment centre in the north are from marginalized ethnic minority groups. We describe and compare socio-demographics, drug use, and sexual practices across ethnic minority people presenting for treatment at the Northern Drug Treatment Center, Mae Rim, Thailand. A prevalence study was conducted between February 1999 and January 2000. Trained interviewers administered a baseline questionnaire to 1,865 people admitted to the Northern Drug Dependence Treatment Center. Ethnic minority (Karen, Akha, Hmong, Lisu, and Lahu) males were included in this analysis (n = 629). Between 7% and 28% of each minority group had ever injected drugs (p = 0.002). Ninety-five per cent of men ever injecting had used heroin. Younger age, speaking Thai language, having a job with higher contact with Thais, and prior drug detoxification were significantly associated with injection in multivariate analysis, while Hmong and Lisu ethnicity were protective. Using occupation and language as proxies, contact with Thais and concomitant acculturation may be a risk for injection among this population. The inadvertent consequences of acculturation as it relates to injection and HIV risk must be addressed.

Methamphetamine users in northern Thailand: changing demographics and risks for HIV and STD among treatment-seeking substance abusers.

Our objective was to determine sociodemographic, sexual and drug-use-related risk factors among methamphetamine (MA) users presenting for drug treatment in northern Thailand. Patients admitted for drug detoxification for MA and other drugs were studied cross-sectionally for risk factors associated with substance abuse and blood-borne and sexually transmitted pathogens. In all, 1865 (200 women) patients treated for MA, opiate, and mixed substance abuse between 1 February 1999 and 31 January 2000 completed all study procedures. Among 1865 participants, 750 (40.2%) were admitted for MA detoxification and 1115 (59.8%) for opiate (heroin, opium, or both) treatment. MA users were significantly younger, better educated, more likely to be Thai than highland ethnic minorities, and had significantly different sexual risks and sexually transmitted disease rates, including lower syphilis seropositivity and higher chlamydial prevalence, than persons admitted for opiate or mixed drug treatment. For those who reported MA use only, use by injection was rare and HIV infections significantly less common than among all other drug users. Thailand is undergoing an epidemic of MA use. These young users are a strikingly different population from opiate/heroin users in northern Thailand. MA users had higher rates of chlamydia infection than opiate users, reflecting their young age, and HIV rates in this population were lower than injecting drug users, but still elevated. MA use is a serious public health problem in Thailand and both improved prevention and treatment methodologies are urgently needed.

HIV incidence and risk behaviours after voluntary HIV counselling and testing (VCT) among adults aged 19-35 years living in peri-urban communities around Chiang Mai city in northern Thailand, 1999.

The Thai government began HIV voluntary counselling and testing (VCT) in all provinces in 1992. We evaluated HIV incidence after participants utilized VCT and its effect on risk behaviours among northern Thai adults aged 19-35 years. A total of 924 men and 1,327 women volunteered to participate in the study. Subjects were counseled, interviewed (socio-demographic, HIV risk behaviour, and HIV testing history), and tested for HIV infection at baseline and at 6 months follow-up. All participants were provided group pre-test counselling; HIV test results were provided in individual confidential post-test counselling. Overall, 329 of 391 men and 621 of 669 women who reported a prior HIV test before participating in our study reported negative results at the previous test. Of these, nine men and 13 women tested positive at baseline, giving incidence rates of 1.04 and 0.69 per 100 person years (PY), respectively. Recent risk behaviour was rare; as a result, the effects of VCT on risk behaviours among the study participants could not be determined. The HIV incidence after VCT among this study population is substantial. Studies to investigate factors associated with HIV incidence among VCT clients could provide insights for more effective HIV prevention.

HIV/AIDS knowledge, attitudes, and practices among Burmese migrant factory workers in Tak Province, Thailand.

Little information is known regarding the level of knowledge among Burmese migrant workers along the Thai/Burma border concerning risk factors, prevention or transmission of HIV. The Burma Medical Association (BMA) and National Health and Education Committee (NHEC) collected data on knowledge, attitudes and practices among 725 factory workers in Tak Province, Thailand during July 2000. We present results from a secondary analysis of these data. Responses were grouped into prevention, transmission and risk categories, and percentages answered correctly were recorded. Men consistently scored higher than women, with significant gender differences in the prevention and transmission questions. Forty-one per cent of the women understood that contraceptive pills do not prevent infection and 15% of females reported ever seeing a condom. Twelve per cent of men and 1.4% of women reported ever using a condom (OR = 8.57, p < 0.0001). Previously, virtually no access has been extended to persons trying to document health status among Burmese migrant workers in factories. The survey reveals a significant lack of knowledge about HIV among factory workers and indicates that a sub-population of Burmese people appears to lack the most basic information about the epidemic.

Precise mapping of recombination breakpoints suggests a common parent of two BC recombinant HIV type 1 strains circulating in China.

Two different BC recombinant HIV-1 strains have arisen and begun to circulate among intravenous drug users in China. The recombinants are mostly subtype C with a few small subtype B segments. Additional full-genome sequences of the two recombinants, termed CRF07_BC and CRFO&_BC, are now available for analysis. Four CRF07_BC strains, including c54, 97CNU01, 98CN009, and a new strain CNGL-179, described here, and four CRF08_BC strains, including 97CNGX-6, 97CNGX-7, 97CNGX-9, and 98CN006, were compared for their recombination breakpoints by bootscanning and software for fine mapping of recombinants. The four CRF07_BC strains shared an identical recombination structure and the four CRF08_BC strains shared an identical, but different, recombination structure. The two CRFs share five precise subtype B/C boundaries, although although other segments differ between them, suggesting that they shared a common ancestor, itself a BC recombinant that separately "back-crossed" onto different subtype C strains. Both CRFs are broadly distributed from north to south in western China and have maintained low interpatient diversity.

Lifetime correlates associated with amphetamine use among northern Thai men attending STD and HIV anonymous test sites.

AIMS: To investigate the demographic, sexual, and other substance use risk correlates of amphetamine use among men in northern Thailand prior to the current epidemic of amphetamine use in the Kingdom. DESIGN: Cross-sectional quantitative behavioral questionnaires. SETTING: Thai Ministry of Health STD and HIV Anonymous Test Sites in the upper northern provinces of Chiang Mai and Lamphun. PARTICIPANTS: Adult Thai men recruited at clinics for enrollment in an HIV seroincidence cohort study (The Thai HIVNET). All men were HIV negative at enrollment, and had at least one self-reported sexual risk for HIV infection (a recent STD, use of sex workers, multiple sexual partners, low or absent condom use, sex with men). MEASUREMENTS: Participants answered a structured questionnaire. FINDINGS: Lifetime history of amphetamine use was reported by 133/914 men, 14.5%. Older age was protective for use (odds ratio (OR) 0.5) and use was associated with use of other substances; heroin (OR 7.1), thinner (OR 6.2), opium (OR 5.9), and marijuana (OR 5.7). Several STDs were associated with amphetamine use: gonorrhea (OR 2.3) and genital warts (OR 2.4), and any STD (OR 1.9). In multivariate analysis, use of heroin (OR 3.1), soft drugs (OR 4.9), and a history of gonorrhea (OR 2.0) were independently associated with amphetamine use in northern Thai men. CONCLUSIONS: Associations between young age, gonorrhea, other substance use and amphetamines indicate that prevention measures could occur at STD clinics and be incorporated into school programs when individuals are entering adolescence.

Shan women and girls and the sex industry in Southeast Asia; political causes and human rights implications.

The human rights abuses which occur during civil conflicts pose special threats to the health and lives of women. These can include rape, sexual violence, increased vulnerability to trafficking into prostitution, and exposure to HIV infection. The long-standing civil conflict in the Shan States of Burma is investigated as a contributing cause to the trafficking of ethnic Shan women and girls into the Southeast Asian sex industry, and to the subsequent high rates of HIV infection found among these women. The context of chronic human rights abuses in the Shan states is explored, as well as the effects of recent forced population transfers on the part of the Burmese Military Regime. Rights abuses specific to trafficked women may further increase their vulnerability to HIV and other STD. The need for a political resolution to the crisis in Burma is discussed, as are approaches aimed at preventing trafficking, empowering women already in the sex industry, and reducing the risks of HIV and other STD among these women and girls.

A recent outbreak of human immunodeficiency virus type 1 infection in southern China was initiated by two highly homogeneous, geographically separated strains, circulating recombinant form AE and a novel BC recombinant.

New outbreaks of human immunodeficiency virus type 1 (HIV-1) among injecting drug users (IDUs) are spreading in China along heroin trafficking routes. Recently, two separate HIV-1 epidemics among IDUs were reported in Guangxi, Southern China, where partial sequencing of the env gene showed subtype C and circulating recombinant form (CRF) AE. We evaluated five virtually full-length HIV-1 genome sequences from IDUs in Guangxi to determine the genetic diversity and the presence of intersubtype recombinants. Sequence analysis showed two geographically separated, highly homogeneous HIV-1 strains. B/C intersubtype recombinants were found in three IDUs from Baise City, in a mountainous region near the Yunnan-Guangxi border. These were mostly subtype C, with portions of the capsid and reverse transcriptase (RT) genes from subtype B. The subtype B portion of the capsid was located in the N-terminal domain, which has been shown to influence virus core maturation, virus infectivity, and binding to cyclophilin A, whereas the subtype B portion of RT was located in the palm subdomain, which is the active site of the enzyme. These BC recombinants differed from a BC recombinant found in Xinjiang Province in northwestern China. CRF AE strains were found in IDUs from Nanning, the capital of Guangxi, and in IDUs from Pingxiang City near the China-Vietnam border. The AE and BC recombinants were both remarkable for their low interpatient diversity, less than 1% for the full genome. Rapid spread of HIV-1 among IDUs may foster the emergence of highly homogeneous strains, including novel recombinants in regions with multiple subtypes.