The present study examined reasons for the high incidence of hepatitis C virus (HCV) infection among young injection drug users (IDUs). IDUs <30 years old who tested negative for HCV antibody were enrolled in a prospective cohort. Risk factors for seroconversion were examined using time-dependent regression analyses: 48 of 195 IDUs seroconverted to HCV, for an incidence rate of 25.1/100 person-years (95% confidence interval, 18.7-32.9/100 person-years). Independent risk factors included sharing needles with an HCV-infected sex partner (borderline statistical significance, P=.11) or a person who was not a sex partner, sharing nonsterile drug-preparation equipment, pooling money with another IDU to buy drugs, and exchanging sex for money. Ubiquitous behaviors among young IDUs, such as the forming of injecting or sexual partnerships and consequent sharing of needles and drug preparation equipment, are risk factors for HCV. Interventions to reduce HCV transmission must recognize the importance of relationships on injecting risk.

Convalescing coronavirus disease 2019 (COVID-19) patients mount robust T cell responses against SARS-CoV-2, suggesting an important role of T cells in viral clearance. To date, the phenotypes of SARS-CoV-2-specific T cells remain poorly defined. Using 38-parameter CyTOF, we phenotyped longitudinal specimens of SARS-CoV-2-specific CD4+ and CD8+ T cells from nine individuals who recovered from mild COVID-19. SARS-CoV-2-specific CD4+ T cells were exclusively Th1 cells and predominantly Tcm cells with phenotypic features of robust helper function. SARS-CoV-2-specific CD8+ T cells were predominantly Temra cells in a state of less terminal differentiation than most Temra cells. Subsets of SARS-CoV-2-specific T cells express CD127, can proliferate homeostatically, and can persist for over 2 months. Our results suggest that long-lived and robust T cell immunity is generated following natural SARS-CoV-2 infection and support an important role of SARS-CoV-2-specific T cells in host control of COVID-19.

Objectives To estimate prevalence and incidence of HIV and sexually transmitted infections (STI) and associated risk factors among young women working as sex workers (SWs) in Phnom Penh, Cambodia. Methods A prospective study of young (<29 years) women working as SWs in brothels, entertainment establishments, and freelance. Sociodemographics, sexual risk, and use of amphetamine-type stimulants (ATS) (“yama” and “crystal”) were assessed by self-report. HIV and STI (Chlamydia trachomatis and Neisseria gonorrhoeae) testing were conducted on blood and urine specimens, respectively. Results Baseline prevalences of HIV, C. trachomatis, and N. gonorrhoeae were 23%, 11.5%, and 7.8%, respectively. HIV incidence was 3.6 per 100 person-years (95% confidence interval [CI], 1.2%– 11.1%); STI incidence was 21.2 per 100 person-years (95% CI, 12.6%– 35.8%). At baseline, 26.5% reported recent ATS use. HIV infection was associated with freelance SW (adjusted odds ratio, 5.85; 95% CI, 1.59–21.58) and younger age of first sex (≤15 years; adjusted odds ratio, 3.06; 95% CI, 1.01–8.46). Incident STI was associated with duration (per year) of SW (adjusted hazard ratio, 1.1; 95% CI, 1.1–1.2) and recent yama use (adjusted hazard ratio, 3.9; 95% CI, 1.5–10.3). Conclusions HIV and STI infection rates were high among SWs working in various settings; freelancers had highest risk. ATS use was associated with incident STI. Venue of sex work and drug prevention should be considered in prevention programs.

Needle-syringe programs (NSP) have been effective in reducing HIV and hepatitis C (HCV) infection among people who inject drugs (PWID). Achieving sustainable reductions in these blood-borne infections requires addressing structural factors so PWID can legally access NSP services. Systematic literature searches collected information on NSP coverage and changes in HIV or HCV infection prevalence or incidence at the population level. Included studies had to document biomarkers (HIV or HCV) coupled with structural-level NSP, defined by a minimum 50 % coverage of PWID and distribution of 10 or more needles/syringe per PWID per year. Fifteen studies reported structural-level NSP and changes in HIV or HCV infection prevalence/incidence. Nine reported decreases in HIV prevalence, six in HCV infection prevalence, and three reported decreases in HIV incidence. The results support NSP as a structural-level intervention to reduce population-level infection and implementation of NSP for prevention and treatment of HIV and HCV infection.

BackgroundThe risk environment framework provides a valuable but under-utilised heuristic for understanding environmental vulnerability to HIV and other sexually transmitted infections among female sex workers. Brothels have been shown to be safer than street-based sex work, with higher rates of consistent condom use and lower HIV prevalence. While entertainment venues are also assumed to be safer than street-based sex work, few studies have examined environmental influences on vulnerability to HIV in this context.MethodsAs part of the Young Women's Health Study, a prospective observational study of young women (15-29 years) engaged in sex work in Phnom Penh, we conducted in-depth interviews (n = 33) to explore vulnerability to HIV/STI and related harms. Interviews were conducted in Khmer by trained interviewers, transcribed and translated into English and analysed for thematic content.ResultsThe intensification of anti-prostitution and anti-trafficking efforts in Cambodia has increased the number of women working in entertainment venues and on the street. Our results confirm that street-based sex work places women at risk of HIV/STI infection and identify significant environmental risks related to entertainment-based sex work, including limited access to condoms and alcohol-related intoxication. Our data also indicate that exposure to violence and interactions with the police are mediated by the settings in which sex is sold. In particular, transacting sex in environments such as guest houses where there is little or no oversight in the form of peer or managerial support or protection, may increase vulnerability to HIV/STI.ConclusionsEntertainment venues may also provide a high risk environment for sex work. Our results indicate that strategies designed to address HIV prevention among brothel-based FSWs in Cambodia have not translated well to street and entertainment-based sex work venues in which increasing numbers of women are working. There is an urgent need for targeted interventions, supported by legal and policy reforms, designed to reduce the environmental risks of sex work in these settings. Future research should seek to investigate sex work venues as risk environments, explore the role of different business models in mediating these environments, and identify and quantify exposure to risk in different occupational settings.

Background Studies of injection drug use cessation have largely sampled adults in drug treatment settings. Little is known about injection cessation and relapse among young injection drug users (IDU) in the community. Methods A total of 365 HCV-negative IDU under age 30 years were recruited by street outreach and interviewed quarterly for a prospective cohort between January 2000 and February 2008. Participants were followed for a total of 638 person-years and 1996 visits. We used survival analysis techniques to identify correlates of injection cessation (≥3 months) and relapse to injection. Results 67% of subjects were male, median age was 22 years (interquartile range (IQR) 20 - 26) and median years injecting was 3.6 (IQR 1.3 – 6.5). 28.8% ceased injecting during the follow-up period. Among those that ceased injecting, nearly one-half resumed drug injection on subsequent visits, one-quarter maintained injecting cessation, and one-quarter were lost to follow-up. Participating in a drug treatment program in the last 3 months and injecting less than 30 times per month were associated with injection cessation. Injecting heroin or heroin mixed with other drugs, injecting the residue from previously used drug preparation equipment, drinking alcohol, and using benzodiazepines were negatively associated with cessation. Younger age was associated with relapse to injection. Conclusion These results suggest that factors associated with stopping injecting involve multiple areas of intervention, including access to drug treatment and behavioral approaches to reduce injection and sustain cessation. The higher incidence of relapse in the younger subjects in this cohort underscores the need for earlier detection and treatment programs targeted to adolescents and transition-age youth.

Background Amphetamine-type stimulant (ATS) use has increased in Cambodia and emerged as a significant problem among female sex workers (FSWs), potentially contributing to increased risk of HIV. We examined the prevalence of ATS use and its effect on sexual risk behaviors, and sexually transmitted infections (STI) among FSWs in Phnom Penh, Cambodia. Methods A one-year prospective study among young women engaged in sex work in brothels, entertainment establishments and on a freelance basis. Socio-demographics, sexual risks, and recent ATS use were assessed by self-report. Blood and urine samples were collected to detect HIV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC). Bivariate and multivariate longitudinal analyses were conducted to assess the effects of ATS use on number of sex partners, inconsistent condom use with paying partners and incident STI. Results ATS use was higher among women working freelance (35.6%) and in brothels (34.8%) compared to women working in entertainment establishments (17.7%) or in multiple venues (14.8%). ATS users reported more sex partners and days drunk in the previous month. In multivariate longitudinal analysis, ATS use was associated with having a higher number of sex partners (Adjusted Risk Ratio 1.49; 95% CI: 1.00–2.21) and incident STI (Adjusted Odds Ratio 5.41; 95% CI: 1.15–25.48), but not inconsistent condom use with paying partner. Conclusion ATS users had more sex partners, high level of alcohol use, and were at increased risk of STI. Our findings underscore ATS use as an important emerging risk exposure that should be integrated into HIV prevention interventions targeting this population.

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