Changes in HIV prevalence and risk among new injecting drug users in a Russian city of high HIV prevalence

OBJECTIVE: To measure HIV prevalence and associated risk factors among recent initiates into drug injecting in 2001 and 2004 in Togliatti City, Russian Federation. DESIGN: Two unlinked, anonymous, cross-sectional, community-recruited surveys of injecting drug users (IDUs) with oral fluid samples for anti-HIV testing. METHODS: IDUs completed an interviewer-administered questionnaire, and oral fluid samples were tested for antibodies to HIV. Demographic characteristics and injecting risk behaviors were compared between subsamples of IDUs who reported injecting for 3 years or less in each of the survey years, 2001 (n = 138) and 2004 (n = 96). Univariable and multivariable analyses explored risk factors with anti-HIV among these new injectors. RESULTS: Among IDUs overall, although HIV prevalence was high, a lower prevalence was found in 2004 (38.5%, 95% confidence interval [CI]: 34.1 to 42.9) than in 2001 (56%, 95% CI: 51.2 to 60.8). A significantly lower prevalence of HIV was found among new injectors in 2004 (11.5%, 95% CI: 5.0 to 17.9) than in 2001 (55.2%, 95% CI: 46.7 to 63.8). Proportionally, fewer new injectors reported injecting daily, injecting with used needles/syringes, and frontloading in 2004 compared with 2001. Decreased odds of anti-HIV were associated with being recruited in 2004 and with a history of drug treatment. Increased odds of HIV were associated with exchanging sex, duration of injection, and frontloading. CONCLUSIONS: Findings indicate a decrease in HIV prevalence among new injectors between 2001 and 2004 and emphasize the role of provision of needle/syringes through pharmacies and providing access to voluntary HIV testing. These findings have implications for other cities in which explosive HIV outbreaks have occurred.     

Requiring help injecting independently predicts incident HIV infection among injection drug users

BACKGROUND: Requiring help injecting has been associated with syringe sharing among injection drug users (IDUs). No prospective study has fully examined this risk factor and its relation to rates of HIV infection. We investigated whether requiring help injecting illicit drugs was a predictor of HIV infection among a prospective cohort of IDUs. METHODS: The Vancouver Injection Drug User Study is a prospective study of more than 1500 IDUs who have been recruited from the Downtown Eastside of Vancouver since May 1996. At baseline and semiannually, subjects provided blood samples and completed an interviewer-administered questionnaire. The questionnaire elicits demographic data as well as information about drug use, HIV risk behavior, and drug treatment. HIV incidence rates were calculated using Kaplan-Meier methods, and Cox regression determined independent predictors of seroconversion. RESULTS: A total of 1013 baseline HIV-negative participants were eligible for this study. Within this population, 418 (41.3%) participants had required help injecting during the last 6 months at baseline. Participants requiring help injecting were more likely to be female (odds ratio = 2.3, 95% confidence interval [CI]: 1.8-3.0; P < 0.001), were slightly younger (33.5 vs. 34.9 years of age; P = 0.014), and had fewer years of experience injecting drugs (7 vs. 11 years; P < or = 0.001). Among participants who required help injecting at baseline, cumulative HIV incidence at 36 months was 16.1% compared with 8.8% among participants who did not require help injecting (log-rank, P < 0.001). In an adjusted model controlling for potential confounding variables, being aboriginal (relative hazard [RH] = 1.68, 95% CI: 1.15-2.48), injecting cocaine daily (RH = 2.71, 95% CI: 1.87-3.95), and requiring help injecting (RH = 1.79, 95% CI: 1.23-2.62) remained independent predictors of HIV seroconversion. CONCLUSIONS: These data demonstrate the need for interventions to reduce the risk of HIV infection among IDUs who require help injecting.     

High prevalence of iron deficiency and anemia among female injection drug users with and without HIV infection

INTRODUCTION: Anemia is associated with increased progression of disease and higher mortality during HIV infection. OBJECTIVE: To determine the prevalence of iron deficiency and iron deficiency anemia among female injection drug users (IDUs) with and without HIV infection. METHODS: Hemoglobin and plasma ferritin were measured in a cross-sectional study of a cohort of female IDUs followed in Baltimore, Maryland. RESULTS: Among 136 HIV-positive and 61 HIV-negative women, the prevalence of anemia was 44.1% and 26.2% ( p <.02), the prevalence of iron deficiency was 37.5% and 42.6% ( p =.49), and the prevalence of iron deficiency anemia was 20.6% and 14.7% ( p =.33), respectively. The overall prevalence of hepatitis C infection was 90.5%. Iron deficiency anemia accounted for 46.7% and 56.1% of the anemia among HIV-positive and HIV-negative female IDUs. CONCLUSIONS: Iron deficiency accounts for about half of the anemia among female IDUS. Although iron supplementation is indicated for anemia patients, such treatment should be approached with caution in women coinfected with HIV and hepatitis C virus, because iron supplementation and overload have been associated with increased progression of HIV infection, worsening of hepatitis C virus infection, and higher mortality.     

High prevalence of HBV and HCV infection among intravenous drug users in Korea

Although intravenous drug users are a well-known route of hepatitis C virus (HCV) and hepatitis B virus (HBV) transmission, there is no data on the prevalence of HBV and HCV infection among intravenous drug users in Korea. In order to describe the prevalence of HBV and HCV infection, and to determine HCV genotypes in the population, serum samples were collected from 107 intravenous drug users during 2005-2006. Fifty-seven percent (n = 61) were HCV RNA positive and 51% (n = 55) were HBV DNA positive. Co-infection of HBV and HCV were found in 23% (n = 25). HCV genotypes 1b, 2a/2c, 2, 2b, and 3a were found in 38% (n = 23), 44% (n = 27), 8% (n = 5), 2% (n = 1), and 3% (n = 2), respectively. Moreover, mixed infections of genotypes 1b and 2a/2c were found in 5% (n = 3). When the number of patients with HCV genotype 1b compared with that of patients with genotype 2a/2c, HBV DNA titer was not significantly different by independent t-test (t = -0.881, P = 0.392 > 0.05) between the two patient groups. These results suggest that the prevalence of HBV and HCV infection among intravenous drug users is high showing over 50% in Korea and a strategic prevention program should be performed in this group to prevent further infection into local community.     

Prevalence and associated clinical characteristics of hepatitis B,C, and HIV infections among injecting drug users in Korea

Injecting drug use is associated with an increased risk of blood‐borne viral infections, such as hepatitis B and C viruses (HBV and HCV, respectively) and human immunodeficiency virus (HIV). However, their prevalence, virological characteristics, and associated factors are not clear among the injecting drug users in Korea. The aim of this study was to determine the prevalence of HBV, HCV, and HIV infection, as well as their virological and clinical characteristics of injecting drug users in South Korea. Between 2007 and 2010, 318 injecting drug users (89.3% male; mean ± age 41.9 ± 8.15 years) were participated. While HIV infection was not found, the seroprevalence of anti‐HCV and HBV surface antigen (HBsAg) was 48.4% (n = 154) and 6.6% (n = 21), respectively. HBV/HCV co‐infection was found in 4.1% (n = 13). Occult HBV infection was suggested in 5.0% (n = 16). Among the HCV genotypes, 1b (37.7%) and 2a/2c (35.7%) were mostly often detected. HCV RNA was detected in 98.1% (n = 151/154) and high‐level viremia (HCV RNA level, ≥400,000 IU/ml) were observed in 59.6% (n = 90/151). In multiple logistic regression analysis, old age (OR 1.18 per year, 95% CI = 1.09–1.27) and ever‐sharing injecting equipment (OR 4.17, 95% CI = 1.39–12.45) independently predicted HCV mono‐infection. The prevalence of HBV and HCV infection were high but largely undiagnosed in the present sample of Korean injecting drug users. Strategic prevention, screening, and treatment are needed to reduce further transmission and morbidity. J. Med. Virol. 85:575–582, 2013. © 2013 Wiley Periodicals, Inc.     

Individual, social, and environmental influences associated with HIV infection among injection drug users in Tijuana, Mexico

OBJECTIVE: We examined correlates of HIV infection among injection drug users (IDUs) in Tijuana, Mexico, a city bordering the United States, which is situated on major migration and drug trafficking routes. METHODS: IDUs aged > or =18 years were recruited using respondent-driven sampling. Participants underwent antibody testing for HIV and syphilis and structured interviews. Weighted logistic regression identified correlates of HIV infection. RESULTS: Of 1056 IDUs, the median age was 37 years, 86% were male, and 76% were migrants. HIV prevalence was higher in female participants than in male participants (8% vs. 3%; P = 0.01). Most IDUs testing HIV-positive were previously unaware of their serostatus (93%). IDUs reported injecting with a median of 2 people in the prior 6 months and had been arrested for having injection stigmata (ie, "track-marks") a median of 3 times. Factors independently associated with HIV infection were being female, syphilis titers consistent with active infection, larger numbers of recent injection partners, living in Tijuana for a shorter duration, and being arrested for having track-marks. CONCLUSIONS: Individual, social, and environmental factors were independently associated with HIV infection among IDUs in Tijuana. These findings suggest the need to intervene not solely on individual risk behaviors but on social processes that drive these behaviors, including problematic policing practices.     

HIV, ethnicity and travel: HIV infection in Vietnamese Australians associated with injecting drug use.

BACKGROUND: The movement of people with their constructed identities including ethnicity has always been one of the determinants of the human immunodeficiency virus (HIV) pandemic. An example of the contributions of travel and ethnicity to experiences of HIV can be seen in the Vietnamese community in Australia. OBJECTIVES: This paper seeks to describe the contributions of ethnicity and travel to the Australian HIV epidemic with particular reference to the evolving epidemic within the Vietnamese Australian community. STUDY DESIGN: We reviewed the available data on the HIV epidemic in Australia with reference to overseas acquisition, ethnicity, the epidemic in the Vietnamese community and the determinants of the current patterns of transmission within this community. RESULTS: Available data suggests that 20-25% of HIV infections notified in Australia are acquired overseas. This proportion is higher in some specific categories such as heterosexually acquired infections. Notification rates are no higher in Vietnamese Australians than in the general Australian population apart from infections associated with injecting drug use (IDU) notified in the state of Victoria. The reasons for this increased rate of notification include increased vulnerability to blood borne virus infection in Australia and the additional, unique risk of frequent travel to Vietnam, a country where IDU carries a high risk of HIV infection. CONCLUSIONS: Australia has succeeded in stabilising the HIV epidemic partly through successful interventions to limit the spread of infection among IDUs. There is now early evidence that HIV transmission may be increasing amongst Vietnamese Australian IDUs. Timely responses that help Vietnamese Australian IDUs reduce their accumulation of risk are likely to be important in determining the level of harm associated with IDU throughout Australia.     

Prevalence and incidence of HIV among out-of-treatment injecting drug users, Chicago 1994-1996

OBJECTIVES: To assess HIV prevalence, incidence, and associated risk factors among IDUs in Chicago. METHODS: Seven hundred ninety-four street-recruited IDUs ranging in age from 18 to 50 years, who were not in drug treatment at study enrollment, were interviewed and tested for HIV at baseline and at two follow-ups scheduled 6 and 12 months after baseline. Questionnaires assessed respondents' demographic characteristics, medical and drug treatment histories, drug use, and sexual practices. RESULTS: HIV seroprevalence at baseline was 18%. Logistic regression identified the following determinants of prevalent HIV infection: Puerto Rican ethnicity, homosexual or bisexual self-identification, injecting for 4 or more years, and having smoked crack cocaine in the past 6 months. Follow-up data were collected from 584 (73.6%) participants. Mean duration of follow-up was 16.5 months, indicating that most subjects had follow-up intervals longer than the scheduled 6 and 12 months. Seven HIV seroconversions were observed in 632 person years of risk, yielding an incidence rate of 1.1 per 100 person years of risk. Injection for 3 or less years was positively associated with HIV seroconversion. CONCLUSIONS: The findings provide evidence of a decline in HIV incidence among IDUs, though newer injectors remain at elevated risk for infection.     

Risk networks and racial/ethnic differences in the prevalence of HIV infection among injection drug users

Studies among injection drug users (IDUs) find a higher prevalence of HIV infection among black and Puerto Rican IDUs than among white IDUs. Risk behaviors seldom explain these differences. We examine how risk networks contribute to racial/ethnic variations in HIV prevalence. Six hundred sixty-two IDUs were recruited on the street in Bushwick (New York City), interviewed, and tested for HIV. Risk behaviors and networks were analyzed to explain racial/ethnic variations in HIV. Forty percent of IDUs were infected with HIV. HIV prevalence was greater for Puerto Ricans (45%) and blacks (44%) than for whites (32%). Egocentric sexual and drug risk networks were predominantly racially/ethnically homogeneous. After multivariate adjustments for risk behaviors and risk networks, black-white differences in HIV prevalence were no longer significant. Although differences between Puerto Ricans and whites persisted, post hoc analyses suggested that network partner characteristics might explain these differences. In Bushwick, racially/ethnically discordant risk partnerships involving black IDUs may function as potential bridges of transmission between groups.     

Methadone maintenance as HIV risk reduction with street-recruited injecting drug users

OBJECTIVE: To compare changes in HIV risk behaviors between street-recruited opiate injectors who entered and remained in methadone maintenance treatment and those who did not. METHODS: Three hundred sixteen participants were interviewed at baseline, received outreach interventions, and were interviewed again 6 months later. RESULTS: Significant (p <.001) reductions in HIV-related risk behaviors, including frequency of injecting, injecting with used (dirty) needles, and sharing injection paraphernalia, were demonstrated. Participants (31%) who entered and remained in methadone maintenance treatment for at least 90 days before follow-up showed a significantly greater reduction in heroin injections than those who did not. They did not show a greater reduction in using dirty needles or sharing other injection paraphernalia. CONCLUSIONS: These findings suggest that although methadone maintenance may reduce injection frequency, it does not reduce other HIV-related risk behaviors above and beyond what can be accomplished through outreach interventions. Treatment facilities and outreach intervention programs should collaborate to provide a comprehensive approach to reducing HIV risk behaviors among drug injectors both in and out of drug treatment.     

High morbidity expected from cirrhosis in injecting drug users

Hepatitis C infection commonly complicates injecting drug use. The outcome of end stage liver disease for this cohort in Ireland has not been estimated. (1) to estimate the prevalence of persistent hepatitis C viraemia and distribution of genotypes in a drug using cohort. (2) To measure the frequency of poor prognostic co-factors. (3) To extrapolate the burden of hepatitis C related disease nationally for this route of infection. A cross section survey of attendees at an East Coast Area drug treatment clinic. Of 94 patients studied (63 male), 70 were hepatitis C antibody positive and 39 were PCR positive. 26 had genotype 1 and 11 had genotype 2 or 3. Most displayed factors associated with a poor prognosis: 72% male, 83% problem drinkers and 87% abnormal liver blood tests. Using published data, we extrapolate over 1,214 cases of cirrhosis via this route of infection nationally, leading to approximately 35, 60 and 50 cases of hepatocellular carcinoma, hepatic decompensation and liver related death respectively per annum. A high prevalence of hepatitis C infection in injecting drug users, compounded by a high frequency of poor prognostic co-factors, means a significant burden of disease can be expected from this group.     

HIV risk reduction in a cohort of injecting drug users in Bangkok,Thailand

OBJECTIVE: To determine changes in risk behavior in relation to study participation among injecting drug users (IDUs) in Bangkok, Thailand. METHODS: During 1995-1996, 1,209 HIV-seronegative IDUs were recruited from Bangkok Metropolitan Administration drug abuse treatment programs to participate in a prospective cohort study. Study visits occurred every 4 months, at which the participants underwent an interview to assess risk behavior and HIV counseling and testing. Eight hundred nine of the IDUs were considered "long-term" participants, who remained in the study through at least the first four scheduled follow-up visits (16 months). Injection risk behavior at each study visit was measured on a four-point scale strongly associated with incident HIV infections in the cohort. Individual regression slopes were used to assess changes in injection risk behavior (risk increase, no change, or risk reduction). RESULTS: Of the 806 long-term study participants, 79% showed declines, 4% showed no change, and 17% showed increases in injection risk behavior. The percentage of participants in the highest-risk category (injecting daily or more frequently and sharing needles and syringes) declined from 42% at baseline to 3% at the final follow-up visit. Being in methadone maintenance treatment was associated with stable low rates of injection risk behavior, while recruitment from the 45-day detoxification treatment was associated with reductions in injection risk behavior. The risk reduction was independent of decline in risk behavior among IDUs in the community at large. CONCLUSIONS: Participation in this cohort study was associated with substantial declines in injection risk behavior. This information is important in the evaluation of possible adverse behavioral effects of participation in future preventive HIV vaccine trials including IDUs, particularly in developing country settings.     

Molecular epidemiology of hepatitis D virus infection among injecting drug users with and without human immunodeficiency virus infection in Taiwan

An outbreak of human immunodeficiency virus (HIV) infection occurred among injecting drug users (IDU) in Taiwan between 2003 and 2006, when an extremely high prevalence of hepatitis C virus (HCV) infection was also detected. To determine whether clusters of hepatitis D virus (HDV) infection occurred in this outbreak, 4 groups of subjects were studied: group 1, HIV-infected IDU (n = 904); group 2, HIV-infected non-IDU (n = 880); group 3, HIV-uninfected IDU (n = 211); and group 4, HIV-uninfected non-IDU (n = 1,928). The seroprevalence of hepatitis B virus (HBV) was 19.8%, 18.4%, 17.1%, and 6.7%, and HDV seroprevalence among HBV carriers was 75.4%, 9.3%, 66.7%, and 2.3%, for groups 1, 2, 3, and 4, respectively. Ninety-nine of 151 (65.6%) HDV-seropositive IDU had HDV viremia: 5 were infected with HDV genotype I, 41 with genotype II, 51 with genotype IV, and 2 with genotypes II and IV. In the phylogenetic analysis, only one cluster of 4 strains within the HDV genotype II was identified. Among patients with HCV viremia, a unique cluster within genotype 1a was observed; yet, patients within this cluster did not overlap with those observed in the HDV phylogenetic analysis. In summary, although IDU had a significantly higher HDV seroprevalence, molecular epidemiologic investigations did not support that HDV was introduced at the same time as HCV among IDU.     

High prevalence of occult hepatitis B virus infection in Taiwanese intravenous drug users

The epidemiology and impact of occult HBV infection in intravenous drug users remain largely unknown. The aim of the study was to investigate the prevalence of occult HBV infection among intravenous drug users in Taiwan. Molecular assays were used to determine the level of serum HBV DNA and the genotype in 304 intravenous drug users negative for both HBsAg and anti-HCV. Of 304 intravenous drug users, 125 (41.1%) were positive for serum HBV DNA. The genotype distribution of HBV was as follows: B, 55 (44%); C, 29 (23%); and mixed B and C infections, 41 (33%). The mean and median serum HBV DNA levels in 125 intravenous drug users with occult HBV infection were 4.0 +/- 0.6 and 4.0 log(10) copies/ml, respectively. The mean serum HBV DNA level in carriers with mixed genotype B and C infections was significantly higher than those infected with HBV genotype B or genotype C alone (mean, 4.2 +/- 0.6 log(10) vs. 3.9 +/- 0.5 log(10), and 3.9 +/- 0.7 log(10) copies/ml, P = 0.01 and 0.05, respectively). The amino acid sequence determination of HBV surface gene in 20 intravenous drug users with occult HBV infection selected at random showed no mutation of amino acid at codon 145. In conclusion, the prevalence of occult HBV infection and mixed HBV genotype infections are not uncommon in intravenous drug users residing in an HBV endemic areas. In addition, intravenous drug users with occult mixed genotype B and C infections have significantly higher viral loads than those with occult infection of single HBV genotype.     

Outbreak of Hepatitis B among injecting drug users in Denmark.

BACKGROUND: The incidence of hepatitis B is low in Denmark, but injecting drug users (IDUs) remains a high-risk group for this infection. OBJECTIVES: The aim of the study was to describe a hepatitis B outbreak among IDUs by comparing existing registers. Additionally, we wanted to analyze the genetic variation of the hepatitis B virus involved in the outbreak. STUDY DESIGN: In the County of Funen, registers of laboratory diagnosis, hospital records and reports from clinicians to the Medical Officer of Health (MOH) were compared between 1992 and 1998. HBsAg positive sera recovered from the epidemic were sequenced and compared to known HBV strains. RESULTS: We identified 648 cases of hepatitis B of which 51% (332) were acute infections. The laboratory database identified 96% (319/332) of these, 45% (150/332) were admitted to hospital and 38% (127/332) were reported to public health. By capture-recapture analysis based on MOH reports and hospital records the estimated total number of acute cases were 334 (95% C.I. 283-385). We sequenced 75 HBsAg positive samples and identified two very similar strains of genotype D (serotype ayw3) among IDUs involved in the outbreak. CONCLUSIONS: The current surveillance system did not detect the majority of acute hepatitis B cases in County of Funen. We suggest laboratory-based surveillance of hepatitis B to be implemented at a national level as this may identify new outbreaks faster and more complete than the current surveillance system.     

High prevalence of HIV, HIV/hepatitis C virus coinfection, and risk behaviors among injection drug users in Chennai, India: a cause for concern

OBJECTIVE: To estimate the prevalence of HIV and hepatitis C virus (HCV) and hepatitis B virus (HBV) coinfections and current risk behaviors among HIV-positive and -negative injection drug users (IDUs) in Chennai, India. METHODS: Cross-sectional analysis of a convenience sample of 912 IDUs recruited between March 2004 and April 2005. Specimens were tested for HIV, HBV, and HCV. Adjusted prevalence ratios (PRs) were estimated using Poisson regression with robust variance estimates. RESULTS: The prevalence of HIV, hepatitis B surface antigen, and anti-HCV were 29.8%, 11.1%, and 62.1%, respectively. Among HIV-infected IDUs, prevalence of coinfection with anti-HCV and hepatitis B surface antigen/anti-HCV were 86% and 9.2%, respectively. In multivariate analysis, injecting at a dealer's place (PR: 1.57) and duration of injection drug use >or=11 years (PR: 3.02) were positively associated with prevalent HIV infection. Contrastingly, alcohol consumption >or=1 per week (PR: 0.55) was negatively associated with HIV. HIV-positive IDUs were as or more likely compared with HIV-negative IDUs to report recent high-risk injection-related behaviors. CONCLUSIONS: There is a high burden of HIV, HCV, and HBV among IDUs that needs to be addressed by improving access to therapies for these infections; furthermore, preventive measures are urgently needed to prevent further spread of HIV, HBV, and HCV in this vulnerable population.     

Incarceration and risk for HIV infection among injection drug users in Bangkok.

OBJECTIVE: To assess potential multiple relationships between incarceration and HIV infection among injecting drug users (IDUs) in Bangkok. Previous cross-sectional studies have shown strong relationships between incarceration and HIV infection but have not been able to assess potential causal pathways. METHODS: Injection drug users seen at methadone treatment programs in Bangkok were screened during 1995 to 1996 for enrollment into the study. With informed consent, 1,209 seronegative IDUs were enrolled in a cohort study to determine HIV incidence and identify factors associated with incident infections. Follow-up visits were conducted every 4 months, with HIV testing and assessment of risk behaviors. RESULTS: Overall incidence rate was 5.8 per 100 person-years (95% confidence interval [CI], 4.8-6.8) of follow-up. A four-step "injection risk" scale was constructed that included less frequent than daily injection, daily injection, daily injection with reported sharing of injection equipment, and injection while incarcerated. This scale was strongly related to HIV incidence, with incidence approximately doubling for each step in the scale. Incidence rate for follow-up periods that contained drug injection while incarcerated was 35/100 person-years at risk. In multivariate analyses, incarceration was related to incident HIV infection in multiple ways: previous incarceration and recent incarceration without drug injection, and the injection risk scale were all independently predictors of incident HIV infection. CONCLUSIONS: Incarceration is related to incident HIV infection through multiple pathways. Previous incarcerations are likely to serve as markers for unmeasured high-risk behaviors, and it is also highly likely that HIV is transmitted during periods of incarceration. Programs to reduce HIV transmission in jails and prisons, including drug abuse treatment of inmates and programs to reduce the likelihood of incarceration of IDUs, are needed urgently. Given the current diffusion of injecting drug use, of HIV infection among drug injectors, and of the common policy of incarcerating drug users, it is very likely that the problem of HIV transmission in jails and prisons is increasing in many countries throughout the world.     

High prevalence of hepatitis E antibodies among Danish prisoners and drug users.

Injecting drug users and prisoners have high prevalences of antibodies to hepatitis A-C. The aim of this study was to determine the prevalence of antibodies to hepatitis E virus (anti-HEV) in two Danish high-risk populations and correlate anti-HEV with risk factors for transmission. Three hundred thirty male prisoners and 137 patients at a drug treatment center were tested for anti-HEV with an in-house enzyme-linked immunoassay (EIA) utilizing antigens derived from open reading frame 2 (ORF2). This was compared with a commercial test with antigens derived from ORF2 and ORF3 (Abbott HEV EIA). In addition the samples were tested for antibodies against hepatitis A-C viruses, human immunodeficiency virus (HIV) 1 and 2, human T lymphotropic virus (HTLV) I and II and herpes simplex virus type 2 (HSV2). The participants were interviewed about risk factors for transmission. The anti-HEV prevalence was 16.9% (95% CI 14-21) for the in-house assay compared to 4.1% (95% CI 2.5-6.3) with the commercial assay. The correlation between the two assays was low (87% overall agreement; kappa value 0.32). One sample was strongly anti-HEV IgM positive, suggesting recent HEV infection inside Denmark. The presence of anti-HEV was associated significantly with anti-HAV among prisoners and increased with age in both groups. In contrast, associations were not found with injecting drug use or sexual risk factors. With the commercial assay an increased prevalence of anti-HEV was found among participants who had spent more than 5 years outside Northern Europe. In conclusion, anti-HEV was highly prevalent among Danish prisoners and drug users but not related to risk factors for blood-borne or sexual transmission.