Prevalence of, and risk factors for, hepatitis C virus infection among recent initiates to injecting in London and Glasgow: cross sectional analysis

Country versus pharmaceutical company interests for hepatitis C treatment

Hepatitis C virus (HCV) is one of the leading causes of liver disease and is responsible for massive health and economic burden worldwide. The disease is asymptomatic in its early stages, but it can progress over time to fatal end-stage liver disease. Thus, the majority of individuals infected with HCV are unaware of their chronic condition. Recent treatment options for HCV can completely cure the infection but are costly. We developed a game model between a pharmaceutical company (PC) and a country striving to maximize its citizens' utility. First, the PC determines the price of HCV treatment; then, the country responds with corresponding screening and treatment strategies. We employed an analytical framework to calculate the utility of the players for each selected strategy. Calibrated to detailed HCV data from Israel, we found that the PC will gain higher revenue by offering a quantity discount rather than using standard fixed pricing per treatment, by indirectly forcing the country to conduct more screening than it desired. By contrast, risk-sharing agreements, in which the country pays only for successful treatments are beneficial for the country. Our findings underscore that policy makers worldwide should prudently consider recent offers by PCs to increase screening either directly, via covering HCV screening, or indirectly, by providing discounts following a predetermined volume of sales. More broadly, our approach is applicable in other healthcare settings where screening is essential to determine treatment strategies.

High-Risk Injection-Related Practices Associated with anti-HCV Positivity among Young Adults Seeking Services in Three Small Cities in Wisconsin

BACKGROUND

Hepatitis C virus (HCV) infection has been increasing among people who inject drugs (PWID), younger than 30 years, and living in rural or suburban areas. We examined injection-related behaviors of young PWID to determine factors associated with HCV infection.

METHODS

From September 2013-May 2015, respondent-driven and snowball sampling were used in 3 suburban areas of Wisconsin to recruit PWID 18-29 years who reported injection drug use in the previous 12 months. Participants were tested for HCV antibody (anti-HCV) and reported injection-related behaviors/practices via self-administered computer-based survey. We calculated anti-HCV prevalence and assessed associated factors using multivariable logistic regression.

RESULTS

Forty-two percent (117/280) of participants were male, 83% (231/280) were white, and median age was 23 years. Overall HCV prevalence was 33%, but HCV prevalence among males was 39%. Adjusting for age, sex, race/ethnicity, education, relationship status, insurance status and income, anti-HCV positivity was associated with higher injection frequency (> 100 times in the past six months) (aOR = 3.07; 95% Confidence Interval (95% CI): 1.72-5.45), ever shared syringes (aOR = 5.15; 95% CI: 2.52-10.51), past week/last use receptive rinse water sharing (aOR = 1.88; 95% CI: 1.06-3.33), past week/last use receptive filter sharing (aOR = 3.25; 95% CI: 1.61-6.54), reusing syringes (aOR = 1.91, 95% CI: 1.08-3.37), history of overdose (aOR = 8.82; 95% CI: 2.26-3.95), and having ever injected another PWID (aOR = 8.82; 95%CI 3.94-19.76).

DISCUSSION

Anti-HCV positivity is associated with high-risk injection practices. Young PWID would benefit from access to evidence-based interventions that reduce their risk of infection, link those infected to HCV treatment, and provide education to reduce further transmission.

New hepatitis C diagnoses in Ontario, Canada are associated with the local prescription patterns of a controlled-release opioid

Increases in acute hepatitis C virus (HCV) incidence may be a result of the rising prevalence of injection drug use and the opioid epidemic. Among persons who inject drugs, sharing of needles/syringes is less common and leads to a smaller proportion of incident cases than does sharing of injection drug preparation equipment. In Canada and Europe, hydromorphone controlled release has been associated with frequent reuse and sharing of IDPE. Drug excipients within HCR have been shown to preserve virus survival within IDPE. We hypothesized that regional differences in HCV incidence would mirror regional differences in HCR prescribing. We reviewed HCV incidence data across Ontario, Canada for 2016. Opioid prescribing patterns in each Health Unit were reviewed. Multivariable Poisson regression analyses were performed to test the strength of hydromorphone controlled release dispensing patterns in explaining HCV incidence compared to all opioids. Less vehicle access, lack of education, lower income, less population density, higher white race/ethnicity and more opioid substitution therapy recipients remained significant positive predictors of hepatitis C incidence in the Ontario model. Higher hydromorphone controlled release dispensing rate was a stronger predictor of HCV incidence than all opioid prescriptions (standardized risk ratio = 1.17, P < .0001 vs sRR = 1.11, P = .02). When hydromorphone controlled release was excluded from the opioid prescription variable, dispensing patterns of all other opioids no longer remained a significant predictor (sRR = 1.042, P = .34). The observed relationship between HCV incidence and hydromorphone controlled release dispensing suggests that the type of opioid prescribed locally may contribute to variations in HCV incidence. These data add support to evidence that hydromorphone controlled release use is contributing to HCV spread in Ontario.

Injection drug network characteristics as a predictor of injection behaviour

Social network characteristics of people who inject drugs (PWID) have previously been flagged as potential risk factors for HCV transmission such as increased injection frequency. To understand the role of the injecting network on injection frequency, we investigated how changes in an injecting network over time can modulate injecting risk behaviour. PWID were sourced from the Networks 2 Study, a longitudinal cohort study of PWID recruited from illicit drug street markets across Melbourne, Australia. Network-related correlates of injection frequency and the change in frequency over time were analysed using adjusted Cox Proportional Hazards and Generalised Estimating Equations modelling. Two-hundred and eighteen PWID followed up for a mean (s.d.) of 2.8 (1.7) years were included in the analysis. A greater number of injecting partners, network closeness centrality and eigenvector centrality over time were associated with an increased rate of infection frequency. Every additional injection drug partner was associated with an increase in monthly injection frequency. Similarly, increased network connectivity and centrality over time was also associated with an increase in injection frequency. This study observed that baseline network measures of connectivity and centrality may be associated with changes in injection frequency and, by extension, may predict subsequent HCV transmission risk. Longitudinal changes in network position were observed to correlate with changes in injection frequency, with PWID who migrate from the densely-connected network centre out to the less-connected periphery were associated with a decreased rate of injection frequency.

Maintaining the healthy body: Blood management and hepatitis C prevention among men who inject performance and image-enhancing drugs

Australia's ambitious aim to 'eliminate' hepatitis C as a public health concern by 2030 requires researchers, policy makers and health practitioners to engage with populations rarely identified as a priority. Men who inject performance and image-enhancing drugs (PIEDs) are one such population, yet research suggests they have low rates of knowledge about hepatitis C. Although rates of needle-sharing in this group are thought to be low, other risks of blood-to-blood contact exist due to the use of large-gauge needles, intramuscular injecting, hard-to-reach injection sites, repeated injecting and peer-to-peer injecting. How should health initiatives engage people who might not customarily consider themselves vulnerable to hepatitis C? Drawing on the work of body theorist Margrit Shildrick, this article considers how men who inject PIEDs understand their bodies, with a particular focus on injecting practices, blood awareness and infection control, in order to inform hepatitis C prevention efforts. In our analysis, we draw on qualitative interviews with 60 men who inject PIEDs, which we conducted for an Australian Research Council-funded project focused on better understanding PIED injecting to improve health and minimise hepatitis C transmission. The interviews suggest that men who inject PIEDs closely monitor potential external infection risks, such as dirt and bacteria that might intrude upon the 'purity and security' of the body. However, less attention appears to be paid to what might be transferred out of the body and potentially to others, such as blood. Notions of trust and cleanliness, and normative perceptions of intravenous drug use, also shaped injecting practices and cursory attention to blood management. While environmental transmission poses a smaller transmission risk than needle-sharing, educating PIED consumers about it is nevertheless warranted. Focusing targeted health promotion materials on environmental blood as a potential route of hepatitis C transmission may help engage this population in prevention, and encourage more frequent hepatitis C testing.

HIV- and hepatitis C-related risk behaviors among people who inject drugs in Uganda: implications for policy and programming

Background

There is a dearth of evidence on injecting drug use and associated HIV and hepatitis C virus (HCV) infections in Uganda. As such, policy and programming for people who inject drugs (PWID) is limited due to scarcity of epidemiological data. We therefore conducted this study to assess the injecting drug and sexual practices among PWID in Kampala Capital City and Mbale Municipality.

Methods

Using a rapid situation assessment framework, we conducted semi-structured interviews among 125 PWID (102 males and 23 females)—recruited through outreach and snowball sampling. We assessed their injecting drug and sexual practices. We also conducted 12 focus group discussions among PWID and 30 in-depth interviews among key informants.

Results

A total of 125 PWID (81.6% males and 18.4% females) were recruited into the study. Approximately three quarters of PWID started injecting before the age of 25. More females (21.7%) compared to males (13.7%) started injecting by the age of 17. Fifty-seven percent of the PWID in Kampala and 50% in Mbale shared injecting equipment in the last 3 months prior to the study. There was an emerging practice of mixing drugs with blood and sharing it among different PWID as a sign of oneness. Heroin was being injected by 72% of the participants. Less than one half of the PWID had used a condom during the last casual sex, and 42.7% did not use a condom the last time they engaged in sex work. Seventy-six percent of the PWID had undertaken an HIV test in the last 12 months, and 9.2% self-reported to be HIV positive.

Conclusions

This study highlights the need for introducing harm reduction policies and services including increased access to sterile injecting equipment and education around safer injecting and sexual practices. Programs for PWID should also address the specific needs of female sex workers who inject drugs.

Introducing hepatitis C virus healthcare pathways in addiction care in the Netherlands with a Breakthrough project: a mixed method study

Background

People who inject drugs (PWID) are disproportionally affected by the hepatitis C virus (HCV) infection. In the Netherlands, active HCV transmission in PWID has practically been halted but uptake of HCV testing and linkage to care remains insufficient in this risk group. A national HCV in Addiction Care (HAC) quality improvement project based on the Breakthrough methodology (i.e. Breakthrough project) aimed to secure proper linkage to care in PWID by introducing local HCV healthcare screening and treatment pathways in addiction care units.

Aim

To qualitatively appraise the local HCV healthcare pathways; to evaluate the yield in terms of number of PWID screened, diagnosed, referred, and treated; and to identify best practices and barriers to successful participation in the HAC Breakthrough project.

Methods

Between 2013 and 2016, 12 units of addiction care centers throughout the Netherlands participated in two series of a HAC Breakthrough project. Local multidisciplinary teams created HCV healthcare pathways. Quality assessment of HCV healthcare pathways was performed retrospectively and data on screening results was collected. In-depth interviews were conducted to elucidate best practices and essential elements for successful participation.

Results

In total, six HCV healthcare pathways were submitted by ten teams of which 83% was judged to be of “good” or “sufficient” quality. Uptake of HCV-antibody screening was 40% (N = 487/1219) and uptake of HCV-RNA in HCV-antibody positives was 59% (N = 107/181). The project resulted in 76 (6%) newly detected cases of persistent HCV viremia. Of all HCV-RNA positives, 92% was referred to a hepatitis treatment center. In 39% (N = 27/70) of those referred, treatment initiation was documented and 82% (N = 22/27) achieved a sustained virological response. Teams identified several best practices including motivational counseling training, oral swabs for anti-HCV testing, facilitating complementary HCV RNA testing, and supervised hospital visits.

Conclusion

The HAC Breakthrough project has brought about good quality HCV healthcare pathways in the majority of participating addiction care centers and has successfully linked PWID with ongoing HCV viremia to care. Uptake of HCV screening and treatment after referral were identified as the main gaps to be closed in the HCV cascade of care to achieve final HCV elimination in Dutch PWID (i.e. micro-elimination).

Recovery of Infectious Hepatitis C Virus From Injection Paraphernalia: Implications for Prevention Programs Serving People Who Inject Drugs

Background

Controlling hepatitis C virus (HCV) transmission among people who inject drugs (PWID) has focused on preventing sharing syringes and drug preparation paraphernalia, but it is unclear whether HCV incidence linked to sharing paraphernalia reflects contamination of the paraphernalia or syringe-mediated contamination when drugs are shared.

Methods

In experiments designed to replicate real-world injection practices when drugs are shared, the residual contents of HCV-contaminated syringes with detachable or fixed needled were passed through the "cookers" and filters used by PWID in preparing drugs for injection and then introduced into a second syringe. All items were tested for the presence of infectious HCV using a chimeric HCV with a luciferase gene.

Results

Hepatitis C virus could not be recovered from cookers regardless of input syringe type or cooker design. Recovery was higher when comparing detachable needles to fixed needles for residue in input syringes (73.8% vs 0%), filters (15.4% vs 1.4%), and receptive syringes (93.8% vs 45.7%).

Conclusions

Our results, consistent with the hypothesis that sharing paraphernalia does not directly result in HCV transmission but is a surrogate for transmissions resulting from sharing drugs, have important implications for HCV prevention efforts and programs that provide education and safe injection supplies for PWID populations.

The risks of HCV infection among Brazilian crack cocaine users: incorporating diagnostic test uncertainty

Despite the initiative by WHO and other international organizations to eliminate HCV in the medium term, hepatitis C infection is still a major public health problem. Even non-injecting drugs users who engage in harmful or addictive drug use are at greater risk of acquiring the infection, when compared to the general population. This study evaluate risk factors for HCV infection in users of crack/cocaine in Brazil, using multilevel models that incorporate variations in the sensitivity and specificity of the respective diagnostic tests. The sample included all the participants of a national survey on street crack cocaine users with serologically reactive result in the rapid test for the HCV as well as 4 non-reactive controls, matched by sex, age category, and major geographic region of residence. Multilevel logistic regression models were used, with and without incorporation of the diagnostic test’s sensitivity and specificity values. The odds of HCV infection were 85% higher among polydrug users, 7.81 times higher among injecting drug users, and 3.69 times higher in those reporting to have genital ulcers. Statistical modeling strategies that incorporate the sensitivity and specificity of diagnostic tests in challenging settings are useful for studying the association between risk factors and infection status.

Polydrug Use and Heterogeneity in HIV Risk Among People Who Inject Drugs in Estonia and Russia: A Latent Class Analysis

Non-medical drug injection is a major risk factor for HIV infection in Russia and Estonia. Multiple drug use (polydrug) has further been associated with increased harms. We compared HIV, injecting and sexual risk associated with polydrug use among people who injected drugs (PWID) in 2012–2013 in Kohtla-Järve (Estonia, n = 591) and St Petersburg (Russia, n = 811). Using latent class analysis, we identified five (poly)drug classes, the largest consisting of single-drug injectors among whom an opioid was the sole drug injected (56% of PWID). The four remaining polydrug classes included polydrug-polyroute injectors who injected and used opiates and stimulants (9%), opiate-stimulant poly-injectors who injected amphetamine-type-stimulants with a primary opiate (7%) and opiate-opioid poly-injectors who injected opioids and opiates (16%). Non-injection stimulant co-users were injectors who also used non-injection stimulants (12%). In multivariable multinomial regressions, all four polydrug classes were associated with greater injection risks than single-drug injection, while opiate-stimulant and opiate-opioid poly-injection were also associated with having multiple sex partners. Riskier behaviours among polydrug-injectors suggest increased potential for transmission of blood-borne and sexually-transmitted infections. In addition to needles/syringes provision, services tailored to PWID drug and risk profiles, could consider drug-appropriate treatment and sexual risk reduction strategies to curb HIV transmission.

Health outcomes associated with crack-cocaine use: Systematic review and meta-analyses

BACKGROUND

Crack-cocaine use is prevalent largely in socio-economically marginalized populations in the Americas. Its use has been associated with diverse health outcomes, yet no recent or systematic reviews of these exist.

METHODS

A systematic review of health outcomes associated with crack-cocaine use was performed, using MEDLINE, Scopus, Web of Science, CINAHL, PsycINFO, and LILACS up to October 2016. Search terms included crack-cocaine and health outcome-related keywords, targeting peer-reviewed studies on quantified health outcomes associated with crack-cocaine use. Random effects meta-analyses produced pooled odds ratios. Levels of evidence for major results were assessed using the GRADE approach. A review protocol was registered with PROSPERO (CRD42016035486).

RESULTS

Of 4700 articles returned, 302 met eligibility criteria, reporting on health outcomes for 14 of 22 ICD-10 chapters. Conclusive evidence and meta-analyses showed positive associations between crack-cocaine use and blood/sexually transmitted diseases (HIV and hepatitis C virus, others); moderate evidence and meta-analyses supported associations with neonatal health, and violence. There were mixed associations for mental and other health outcomes, yet insufficient evidence to perform meta-analyses for many categories (e.g., mortality). Most underlying research was of limited or poor quality, with crack-cocaine commonly assessed as a secondary covariate.

CONCLUSIONS

Crack-cocaine use was associated with a range of health outcomes, although it was unclear if there was direct causal impact, interactions between risk factors, or external drivers of both crack-cocaine use and outcomes. Rigorous epidemiological studies are needed to systematically assess health outcomes of crack-cocaine use and underlying pathways, also to inform evidence-based interventions.

Preventing blood-borne virus infection in people who inject drugs in the UK: systematic review, stakeholder interviews, psychosocial intervention development and feasibility randomised controlled trial

BACKGROUND

Opioid substitution therapy and needle exchanges have reduced blood-borne viruses (BBVs) among people who inject drugs (PWID). Some PWID continue to share injecting equipment.

OBJECTIVES

To develop an evidence-based psychosocial intervention to reduce BBV risk behaviours and increase transmission knowledge among PWID, and conduct a feasibility trial among PWID comparing the intervention with a control.

DESIGN

A pragmatic, two-armed randomised controlled, open feasibility trial. Service users were Steering Group members and co-developed the intervention. Peer educators co-delivered the intervention in London.

SETTING

NHS or third-sector drug treatment or needle exchanges in Glasgow, London, Wrexham and York, recruiting January and February 2016.

PARTICIPANTS

Current PWID, aged ≥ 18 years.

INTERVENTIONS

A remote, web-based computer randomisation system allocated participants to a three-session, manualised, psychosocial, gender-specific group intervention delivered by trained facilitators and BBV transmission information booklet plus treatment as usual (TAU) (intervention), or information booklet plus TAU (control).

MAIN OUTCOME MEASURES

Recruitment, retention and follow-up rates measured feasibility. Feedback questionnaires, focus groups with participants who attended at least one intervention session and facilitators assessed the intervention's acceptability.

RESULTS

A systematic review of what works to reduce BBV risk behaviours among PWID; in-depth interviews with PWID; and stakeholder and expert consultation informed the intervention. Sessions covered improving injecting technique and good vein care; planning for risky situations; and understanding BBV transmission. Fifty-six per cent (99/176) of eligible PWID were randomised: 52 to the intervention group and 47 to the control group. Only 24% (8/34) of male and 11% (2/18) of female participants attended all three intervention sessions. Overall, 50% (17/34) of men and 33% (6/18) of women randomised to the intervention group and 47% (14/30) of men and 53% (9/17) of women randomised to the control group were followed up 1 month post intervention. Variations were reported by location. The intervention was acceptable to both participants and facilitators. At 1 month post intervention, no increase in injecting in 'risky' sites (e.g. groin, neck) was reported by participants who attended at least one session. PWID who attended at least one session showed a trend towards greater reduction in injecting risk behaviours, a greater increase in withdrawal planning and were more confident about finding a vein. A mean cost of £58.17 per participant was calculated for those attending one session, £148.54 for those attending two sessions and £270.67 for those attending all three sessions, compared with £0.86 in the control group. Treatment costs across the centres vary as a result of the different levels of attendance, as total session costs are divided by attendees to obtain a cost per attendee. The economic analysis suggests that a cost-effectiveness study would be feasible given the response rates and completeness of data. However, we have identified aspects where the service use questionnaire could be abbreviated given the low numbers reported in several care domains. No adverse events were reported.

CONCLUSIONS

As only 19% of participants attended all three intervention sessions and 47% were followed up 1 month post intervention, a future definitive randomised controlled trial of the intervention is not feasible. Exposure to information on improving injecting techniques did not encourage riskier injecting practices or injecting frequency, and benefits were reported among attendees. The intervention has the potential to positively influence BBV prevention. Harm reduction services should ensure that the intervention content is routinely delivered to PWID to improve vein care and prevent BBVs.

FUTURE WORK

The intervention did not meet the complex needs of some PWID, more tailoring may be needed to reach PWID who are more frequent injectors, who are homeless and female.

LIMITATIONS

Intervention delivery proved more feasible in London than other locations. Non-attendance at the York trial site substantially influenced the results.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN66453696 and PROSPERO 014:CRD42014012969.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 72. See the NIHR Journals Library website for further project information.

High hepatitis C incidence in relation to prescription opioid injection and poly-drug use: Assessing barriers to hepatitis C prevention

BACKGROUND

Prescription opioid (PO) injection and poly-drug use have been associated with hepatitis C virus (HCV) infection among people who inject drugs (PWID). Poly-drug use is often a barrier to key HCV preventive programmes including opioid agonist treatment. The contribution of specific drug combinations to high HCV incidence in poly-drug users has not been assessed previously. Addressing this knowledge gap could enhance HCV treatment and prevention efforts. We examined the association between specific drugs and number of drugs used in addition to injected POs, and HCV seroconversion.

METHODS

PWID participating in a cohort study in Montréal (HEPCO), HCV-seronegative at baseline and followed between 2004 and 2013, were included. Data were collected by interview-administered questionnaires. Blood samples were tested for HCV new infections at each 3-6 month follow-up visit. Time-varying Cox regression models were utilized.

RESULTS

Of 356 participants (81.5% males; mean age: 34.7 years), 123 (34.6%) reported injected POs in the past month at baseline. In univariate analyses, recent use of the following drugs was associated with HCV seroconversion: injected POs, injected cocaine, injected heroin, non-injected tranquilisers, and smoked crack/cocaine. The relative excess risk of HCV seroconversion due to interaction (RER1_HR) was the highest for co-use of injected POs with the following substances: injected cocaine (RER1_HR=3.44), smoked crack/cocaine (RER1_HR=1.27), and non-injected tranquilisers (RER1_HR=0.8). In addition, a significant linear trend (p<0.001) towards higher risk was observed with increasing the number of these three drugs used in combination with injected POs.

CONCLUSION

Specific drugs and number of drugs used in addition to injected POs play a modulating role in the risk of HCV primary infection. Poly-drug use among people who inject POs has to be addressed in order to improve harm reduction programmes and reduce HCV transmission in this high-risk population.

The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs

With the development of new highly efficacious direct-acting antiviral (DAA) treatments for hepatitis C virus (HCV), the concept of treatment as prevention is gaining credence. To date, the majority of mathematical models assume perfect mixing, with injectors having equal contact with all other injectors. This article explores how using a networks-based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Using observational data, we parameterized an exponential random graph model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were (1) treat randomly selected nodes and (2) "treat your friends," where an individual is chosen at random for treatment and all their infected neighbors are treated. As treatment coverage increases, HCV prevalence at 10 years reduces for both the high- and low-efficacy treatment. Within each set of parameters, the treat your friends strategy performed better than the random strategy being most marked for higher-efficacy treatment. For example, over 10 years of treating 25 per 1,000 PWID, the prevalence drops from 50% to 40% for the random strategy and to 33% for the treat your friends strategy (6.5% difference; 95% confidence interval: 5.1-8.1).

CONCLUSION

Treat your friends is a feasible means of utilizing network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment, such an approach will benefit not just the individual, but also the community more broadly by reducing the prevalence of HCV among PWID.

Detection of HCV-Specific IFN-γ Responses in HCV Antibody and HCV RNA Negative Injecting Drug Users

BACKGROUND

Detectable HCV-specific cellular immune responses in HCV antibody and RNA negative people who inject drugs (PWID) raise the question of whether some are resistant to HCV infection. Immune responses from people who have been exposed to hepatitis C virus (HCV) and remain anti-HCV negative are of interest for HCV vaccine development; however, limited research addresses this area.

OBJECTIVES

In a cohort of HCV antibody and RNA negative PWID, we assessed whether the presence of HCV-specific IFN-γ responses or genetic associations provide any evidence of protection from HCV infection.

PATIENTS AND METHODS

One hundred and ninety-eight participants were examined longitudinally for clinical, behavioral, social, environmental and genetic characteristics (IFNL3 genotype [formally IL-28B] and HLA type). Sixty-one of the 198 participants were HCV antibody and RNA negative, with 53 able to be examined longitudinally for HCV-specific IFN-γ ELISpot T cell responses.

RESULTS

Ten of the 53 HCV antibody and RNA negative participants had detectable HCV-specific IFN-γ responses at baseline (18%). The magnitude of IFN-γ responses averaged 131 +/- 96 SFC/106 PBMC and the breadth was mean 1 +/- 1 pool positive. The specificity of responses were mainly directed to E2, NS4b and NS5b. Participants with (10) and without (43) HCV-specific IFN-γ responses did not differ in behavioral, clinical or genetic characteristics (P > 0.05). There was a larger proportion sharing needles (with 70%, without 49%, P = 0.320) and a higher incidence of HCV (with 35.1 per 100 py, 95% CI 14.6, 84.4, without 16.0 per 100 py, 95% CI 7.2, 35.6, P = 0.212) in those with IFN-γ responses, although not statistically significant. Half the participants with baseline IFN-γ responses became HCV RNA positive (5/10), with one of these participants spontaneously clearing HCV. The spontaneous clearer had high magnitude and broad Th1 responses, favorable IFNL3 genotype and favorable HLA types.

CONCLUSIONS

This study demonstrated the detection of HCV-specific IFN-γ responses in HCV antibody and RNA negative individuals, with a tendency for HCV-specific IFN-γ responses to be associated with HCV exposure. The potential role of HCV-specific IFN-γ responses in those who remained HCV RNA negative is of value for the development of novel HCV therapeutics.

High rates of hepatitis C virus reinfection and spontaneous clearance of reinfection in people who inject drugs: a prospective cohort study

Hepatitis C virus reinfection and spontaneous clearance of reinfection were examined in a highly characterised cohort of 188 people who inject drugs over a five-year period. Nine confirmed reinfections and 17 possible reinfections were identified (confirmed reinfections were those genetically distinct from the previous infection and possible reinfections were used to define instances where genetic differences between infections could not be assessed due to lack of availability of hepatitis C virus sequence data). The incidence of confirmed reinfection was 28.8 per 100 person-years (PY), 95%CI: 15.0-55.4; the combined incidence of confirmed and possible reinfection was 24.6 per 100 PY (95%CI: 16.8-36.1). The hazard of hepatitis C reinfection was approximately double that of primary hepatitis C infection; it did not reach statistical significance in confirmed reinfections alone (hazard ratio [HR]: 2.45, 95%CI: 0.87-6.86, p=0.089), but did in confirmed and possible hepatitis C reinfections combined (HR: 1.93, 95%CI: 1.01-3.69, p=0.047) and after adjustment for the number of recent injecting partners and duration of injecting. In multivariable analysis, shorter duration of injection (HR: 0.91; 95%CI: 0.83-0.98; p=0.019) and multiple recent injecting partners (HR: 3.12; 95%CI: 1.08-9.00, p=0.035) were independent predictors of possible and confirmed reinfection. Time to spontaneous clearance was shorter in confirmed reinfection (HR: 5.34, 95%CI: 1.67-17.03, p=0.005) and confirmed and possible reinfection (HR: 3.10, 95%CI: 1.10-8.76, p-value=0.033) than primary infection. Nonetheless, 50% of confirmed reinfections and 41% of confirmed or possible reinfections did not spontaneously clear.

Conclusions: Hepatitis C reinfection and spontaneous clearance of hepatitis C reinfection were observed at high rates, suggesting partial acquired natural immunity to hepatitis C virus. Public health campaigns about the risks of hepatitis C reinfection are required.

Injection of drug residue as a potential risk factor for HCV acquisition among Montréal young injection drug users

BACKGROUND

Preparing drugs or medications for injection may leave residues in containers and filters used by injection drug users (IDUs). Little is known about the specific practice of injecting someone else's drug residue as a possible route of HCV transmission.

METHODS

A prospective cohort study of street youth aged 14-23 years old was carried out between July 2001 and December 2005. For this analysis, youth who injected in the six months prior to interview were selected if they were HCV-negative and had completed at least one follow-up visit. Semi-annual visits involved completing an interviewer-administered questionnaire and providing a blood sample for HCV antibody testing. "Sharing behaviors" (any injection preparation behavior that could entail IDUs using injection equipment used by others) including injecting someone else's drug residue were assessed at each interview. Predictors of HCV seroconversion were identified using Cox proportional hazards regression analyses. Two multivariate models were built, one considering sharing behaviors only, and one with cocaine injection forced into it.

RESULTS

Of the 175 participants, 60% were male and their mean age was 20.7years old. In both models, residue injection was a predictor of HCV incidence, although with marginal statistical significance. The adjusted hazard ratio estimates were (2.15; 95% CI 0.99-4.67) and (2.11; 95% CI 0.97-4.62) respectively.

CONCLUSION

This epidemiological study underscores the role injection of drug residue may play in HCV transmission among IDUs. In the current context of the worldwide HCV epidemics, this question deserves further investigation.

The rising prevalence of prescription opioid injection and its association with hepatitis C incidence among street-drug users

AIMS

  To examine trends in prescription opioid (PO) injection and to assess its association with hepatitis C virus (HCV) seroconversion among injection drug users (IDUs).

DESIGN

  Prospective cohort study.

SETTING

  Montreal, Canada.

PARTICIPANTS

  HCV-negative IDUs at baseline, reporting injection in the past month.

MEASUREMENTS

  Semi-annual visits included HCV antibody testing and an interview-administered questionnaire assessing risk behaviours. HCV incidence rate was calculated using the person-time method. Time-updated Cox regression models were conducted to examine predictors of HCV incidence.

FINDINGS

  The proportion of IDUs reporting PO injection increased from 21% to 75% between 2004 and 2009 (P < 0.001). Of the 246 participants (81.6% male; mean age 34.5 years; mean follow-up time 23 months), 83 seroconverted to HCV [incidence rate: 17.9 per 100 person-years; 95% confidence interval (CI) 14.3, 22.1]. Compared to non-PO injectors, PO injectors were more likely to become infected [adjusted hazard ratio (AHR): 1.87; 95%CI:1.16, 3.03]. An effect modification was also found: PO injectors who did not inject heroin were more likely to become infected (AHR: 2.88; 95%CI: 1.52, 5.45) whereas no association was found for participants using both drugs (AHR: 1.19; 95% CI: 0.61, 2.30). Other independent predictors of HCV incidence were: cocaine injection, recent incarceration and >30 injections per month.

CONCLUSIONS

  Prescription opioid injectors who do not inject heroin are at greater risk for HCV seroconversion than are those injecting both heroin and prescription opioids. Important differences in age, behaviour and social context suggest a need for targeted outreach strategies to this population.

Estimating the variability in the risk of infection for hepatitis C in the Glasgow injecting drug user population

Glasgow (Scotland's largest city) has a high prevalence of injecting drug use and has one of the highest prevalences of hepatitis C virus (HCV) infection in injecting drug users (IDUs) in Western Europe. HCV prevalence data from surveys of Glasgow's IDUs from 1990 to 2007 were utilized and a model was applied that described the prevalence of HCV as a function of the rate (force) of infection. Force-of-infection estimates for HCV that may vary over time and injecting career length over a range of variables were investigated. New initiates to injecting were found to be at increased risk of HCV infection, with being recruited from a street location and reporting injecting in prison leading to a significant increase in the risk of infection in new initiates. These results indicate areas of importance for the planning of public health measures that target the IDU population.

Examining hepatitis C virus testing practices in primary care clinics

Prior studies found that hepatitis C virus (HCV) risk assessment and testing in primary care clinics were suboptimal. We aimed to determine the actual HCV testing rate among patients with HCV risk factors and to identify variables predictive of testing. In order to do so, we performed a prospective cohort study among patients seen in four urban primary care clinics. At the initial visit, patients were given a questionnaire that listed HCV risk factors and they were instructed to check 'yes' or 'no' if they did or did not have a risk factor, respectively. Patients then handed this questionnaire to their physician during their initial visit. Among those who acknowledged having a HCV risk factor via the questionnaire, we determined the subsequent HCV testing rate and calculated adjusted odds ratios (aOR) with 95% confidence intervals (CI) to identify variables predictive of testing. Of the 578 individuals who acknowledged having a HCV risk factor via the questionnaire, only 8% (46/578) were tested for HCV within 2 months of their initial visit. Among those tested, 11% (5/46) had a positive HCV antibody test result. The only variable predictive of HCV testing after adjusting for confounders was having a specific HCV risk factor identified and documented in the chart by physicians [16% (26/159) vs 5% (20/419); aOR 4.5, 95% CI 2.1-9.5]. In summary, 92% of patients with a HCV risk factor were not tested for HCV in the primary care setting, and efforts to improve such rates are clearly warranted.

Hepatitis C virus infection in the Middle East and North Africa "MENA" region: injecting drug users (IDUs) is an under-investigated population

PURPOSE

Investigation of the injecting drug users (IDUs) population is becoming extremely critical and timely in light of the recent evidence that IDUs now act as the core of hepatitis C virus (HCV) epidemics in developed countries. The purpose of this article, therefore, is not only to review the epidemiology of HCV in the Middle East and North Africa (MENA) region, but also to see whether IDUs were adequately studied and whether harm reduction strategies to be applied for their protection have been set.

METHODS

A literature review was carried out of articles published within the last decade on HCV infection.

RESULTS

The gathered data showed that the population of IDUs is severely under-investigated throughout the whole region, possibly due to religious and cultural impediments.

CONCLUSION

In order to reduce the risk of HCV infection in IDUs, a set of recommendations are advanced emphasizing the urgent need for bio-behavioral studies in this population in order to help identify the source and mode of transmission and the genotypes of HCV involved. These results may allow the development of effective and, yet, socially acceptable intervention strategies. We believe that the role which IDUs play in sustaining HCV infection is also an under-investigated topic in many developing countries. Similar reviews and, hence, interventions should be initiated in these regions.

Minimal transmission of HIV despite persistently high transmission of hepatitis C virus in a Swedish needle exchange program

The aim of this study was to examine the prevalence and incidence of HIV and hepatitis B and C (HBV and HCV) among injecting drug users in a Swedish needle exchange programme (NEP) and to identify risk factors for blood-borne transmission. A series of serum samples from NEP participants enrolled from 1997 to 2005 were tested for markers of HIV, HBV and HCV (including retrospective testing for HCV RNA in the last anti-HCV-negative sample from each anti-HCV seroconverter). Prevalence and incidence were correlated with self-reported baseline characteristics. Among 831 participants available for follow-up, one was HIV positive at baseline and two seroconverted to anti-HIV during the follow-up of 2433 HIV-negative person-years [incidence 0.08 per 100 person-years at risk (pyr); compared to 0.0 in a previous assessment of the same NEP covering 1990-1993]. The corresponding values for HBV were 3.4/100 pyr (1990-1993: 11.7) and for HCV 38.3/100 pyr (1990-1993: 27.3). HCV seroconversions occurred mostly during the first year after NEP enrolment. Of the 332 cases testing anti-HCV negative at enrolment, 37 were positive for HCV RNA in the same baseline sample (adjusted HCV incidence 31.5/100 pyr). HCV seroconversion during follow-up was significantly associated with mixed injection use of amphetamine and heroin, and a history of incarceration at baseline. In this NEP setting, HIV prevalence and incidence remained low and HBV incidence declined because of vaccination, but transmission of HCV was persistently high. HCV RNA testing in anti-HCV-negative NEP participants led to more accurate identification of timepoints for transmission.

The impact of needle and syringe provision and opiate substitution therapy on the incidence of hepatitis C virus in injecting drug users: pooling of UK evidence

AIMS

To investigate whether opiate substitution therapy (OST) and needle and syringe programmes (NSP) can reduce hepatitis C virus (HCV) transmission among injecting drug users (IDUs).

DESIGN

Meta-analysis and pooled analysis, with logistic regression allowing adjustment for gender, injecting duration, crack injecting and homelessness.

SETTING

Six UK sites (Birmingham, Bristol, Glasgow, Leeds, London and Wales), community recruitment.

PARTICIPANTS

A total of 2986 IDUs surveyed during 2001-09.

MEASUREMENT

Questionnaire responses were used to define intervention categories for OST (on OST or not) and high NSP coverage (≥100% versus <100% needles per injection). The primary outcome was new HCV infection, measured as antibody seroconversion at follow-up or HCV antibody-negative/RNA-positive result in cross-sectional surveys.

FINDINGS

Preliminary meta-analysis showed little evidence of heterogeneity between the studies on the effects of OST (I2=48%, P=0.09) and NSP (I2=0%, P=0.75), allowing data pooling. The analysis of both interventions included 919 subjects with 40 new HCV infections. Both receiving OST and high NSP coverage were associated with a reduction in new HCV infection [adjusted odds ratios (AORs)=0.41, 95% confidence interval (CI): 0.21-0.82 and 0.48, 95% CI: 0.25-0.93, respectively]. Full harm reduction (on OST plus high NSP coverage) reduced the odds of new HCV infection by nearly 80% (AOR=0.21, 95% CI: 0.08-0.52). Full harm reduction was associated with a reduction in self-reported needle sharing by 48% (AOR 0.52, 95% CI: 0.32-0.83) and mean injecting frequency by 20.8 injections per month (95% CI: -27.3 to -14.4).

CONCLUSIONS

There is good evidence that uptake of opiate substitution therapy and high coverage of needle and syringe programmes can substantially reduce the risk of hepatitis C virus transmission among injecting drug users. Research is now required on whether the scaling-up of intervention exposure can reduce and limit hepatitis C virus prevalence in this population.

Differences in drug consumption, comorbidity and health service use of opioid addicts across six European urban regions (TREAT-project)

OBJECTIVES

This comparative study investigated consumption patterns, comorbidity and treatment utilization of opioid addicts in six European cities (Athens, Essen, London, Padua, Stockholm, Zurich).

SUBJECTS AND METHODS

Data were collected by structured face-to-face interviews. The representative sample comprises 599 addicts (100 patients per centre, 99 in London) at the start of a treatment episode.

RESULTS

Patients were dependent on opioids for about 10 years. Regional differences were significant regarding the patients' drug consumption pattern and their method of heroin administration (up to a fourth of the patients in Essen, London and Zurich usually smoke heroin). Concomitant use of benzodiazepines, cannabis and alcohol was common in all regions with the German and English samples showing the highest level of polydrug use. The prevalence of major depression was high in all regions (50%). Stockholm and London patients worry most about their physical health. Differences in the amount of needle sharing and especially in the use of public health service were prominent between the sites. Opioid addiction was a long-term disorder associated with a high burden of comorbidity and social problems in all cities.

CONCLUSION

The results of the study show significant interregional differences of opioid addicts which might require different treatment strategies in European countries to handle the problem.

HIV vaccine trial willingness among injection and non-injection drug users in two urban centres, Barcelona and San Francisco

Being able to recruit high-risk volunteers who are also willing to consider future participation in vaccine trials are critical features of vaccine preparedness studies. We described data from two cohorts of injection- and non-injection drug users in Barcelona, Spain [Red Cross centre] and in San Francisco, USA, [UFO-VAX study] at high risk of HIV/HCV infection to assess behaviour risk exposure and willingness to participate in future preventive HIV vaccine trials. We successfully identified drug-using populations that would be eligible for future HIV vaccine efficacy trials, based on reported levels of risk during screening and high levels of willingness to participate. In both groups, Red Cross and UFO-VAX respectively, HCV infection was highly prevalent at baseline (41% and 34%), HIV baseline seroprevalence was 4.2% and 1.5%, and high levels of willingness were seen (83% and 78%).

Pilot study assessing HIV vaccine trial readiness among female sex workers, injection and non-injection drug users, and men who have sex with men in Spain

The purpose of this study was to assess HIV risk and willingness to participate in HIV vaccine trials in three high risk populations in Spain. Eight hundred and forty-four participants, comprising female sex workers, injection and non-injection drug users (IDUs and NIDUs, respectively), and men who have sex with men were tested for HIV and surveyed for risk and willingness to participate in future preventive HIV vaccine trials. HIV seroprevalence was 3.8% (95% CI: 2-11). HIV infection was associated with transgender identification, IDU in the past year, and sex with an IDU or other drug-using partner. The majority (82%) expressed their willingness to participate in HIV vaccine trials. Substantial sexual and parenteral risk in all groups and concomitant willingness to participate in vaccine trials was found, particularly among women and IDUs. Additional longitudinal cohort studies in Spain are needed to plan future vaccine efficacy trials.

Hepatitis C virus incidence among young street-involved IDUs in relation to injection experience

BACKGROUND

Young injection drug users (IDUs) are at very high risk of hepatitis C virus (HCV) infection. Using a time scale starting at first injection, we studied the period of HCV susceptibility after initiation into drug injection among street-involved IDUs.

METHODS

A prospective cohort study was carried out among street youth from 2001 to 2005. Semiannual interviews included completion of an interviewer-administered questionnaire and collection of blood samples for HCV antibody testing. HCV-negative subjects currently injecting drugs (last six months) were included in the analyses. Follow-up started at first questionnaire where current injection was reported and ended at seroconversion or at last questionnaire. Poisson regression was used to assess the predictive power of time elapsed since initiation on incidence rate. Kaplan-Meier technique was used to estimate cumulative infection probabilities.

RESULTS

Among the 858 cohort participants, 145 were injecting at baseline and 60 were injecting at a subsequent questionnaire (45 youth had started injection and 15 had resumed injection). Mean age was 20 years and 62% were males. In the 395 person-years of follow-up, 61 subjects contracted HCV. The HCV incidence rate increased from 16.1/100 person-years during the first year following first injection to 22.4 in the third year, and then decreased to 7.2 in years 7-13 (p=0.02). Median time to seroconversion after first injection was 3.3 years.

CONCLUSION

The first years after first injection is the period during which vulnerability to HCV is greatest. Our results show the importance of intervening with new IDUs to optimize the chances to successfully prevent infection.

High incidence of hepatitis C virus reinfection in a cohort of injecting drug users

An estimated 170 million people worldwide carry the hepatitis C virus (HCV), and in more developed countries the prevalence and incidence of HCV is particularly high among injecting drug users (IDUs). Spontaneous clearance of HCV infection and reinfection is well recognized but the level of protection against further infection conferred by HCV infection and clearance remains uncertain. We conducted a prospective study of HCV infection in IDUs recruited in Melbourne, Australia, using a much shorter median testing interval than in previous studies. Incidences of naive infection and reinfection were calculated by the person-year method and Cox proportional hazards regression used to adjust for covariates. A significantly higher HCV incidence rate was measured in previously infected IDUs (46.8% per year) compared with HCV-naive IDUs (15.5% per year). The hazard ratio for previously infected IDUs compared to HCV-naive IDUs, after adjustment for time-dependent covariates, was 2.54 (95% confidence interval, 1.11-5.78, P > |z| < 0.05). Viral persistence after reinfection appeared similar to that following naive infection.

CONCLUSION

Our data suggest that HCV infection in IDUs is more likely following prior infection and clearance than in HCV-naive individuals, implying no increased immunity against further infection. This result has important implications for the future development of an HCV vaccine.

Capture—recapture and anchored prevalence estimation of injecting drug users in England: national and regional estimates

Capture—recapture (C—RC) using four data sources, one of which accounted for 81% of captured injectors, and multiple indicator methods (MIM) were used to obtain national, regional and local estimates of the prevalence of injecting drug use among opiate and/or crack cocaine users in England. Persons aged 15 to 64 years, in contact with health and/or criminal justice services during 2005/2006, and known to be using opiates and/or crack cocaine and injecting drugs were included in the C—RC analysis. The MIM analysis included indicators relating to drug treatment, drug-related deaths, population density and drug offences.

There were an estimated 130,000 opiate and/or crack cocaine users who injected drugs in 2005/06 (95% confidence interval 125,800 to 137,000), corresponding to 3.9 per thousand of the population aged 15 to 64 years (95% confidence interval 3.8—4.1). Regional variation in the prevalence of injecting was evident, ranging from 6.1 per thousand of the population aged 15 to 64 years in Yorkshire and the Humber (95% confidence interval 5.6 to 6.6) to 2.3 per thousand in the East of England (95% confidence interval 1.8 to 2.9). Application of gender and age-group distributions for treated injecting drug users (IDUs) to the prevalence estimates suggested that there were 97,200 male injectors (95% confidence interval 94,000 to 102,500) and 63,600 female injectors aged 25 to 34 years (95% confidence interval 61,500 to 67,000).

The prevalence estimates provide a basis from which numbers of current IDUs infected with hepatitis C virus (HCV) can be approximated.

Meta-regression of hepatitis C virus infection in relation to time since onset of illicit drug injection: the influence of time and place

The authors examined the relation between time since onset of illicit drug injection (time at risk) and rates of hepatitis C virus (HCV) infection by using meta-regression. In 72 prevalence studies, median time since onset of injection was 7.24 years and median prevalence was 66.02%. The model showed statistically significant linear and quadratic effects of time at risk on HCV prevalence and significantly higher prevalence in developing and transitional countries and in earlier samples (1985-1995). In developed countries post-1995, mean fitted prevalence was 32.02% (95% confidence interval: 25.31, 39.58) at 1 year of injection and 53.01% (95% confidence interval: 40.69, 65.09) at 5 years. In developing/transitional countries post-1995, mean fitted HCV prevalence was 59.13% (95% confidence interval: 30.39, 82.74) at 1 year of injection. In 10 incidence studies, median time at risk was 5.29 years and median cumulative HCV incidence was 20.69%. Mean fitted cumulative incidence was 27.63% (95% confidence interval: 16.92, 41.70) at 1 year of drug injection. The authors concluded that time to HCV infection in developed countries has lengthened. More rapid onset of HCV infection in drug injectors in developing/transitional countries resembles an earlier era of the HCV epidemic in other regions.

Where are people being tested for anti-HCV in England? Results from sentinel laboratory surveillance

Many people infected with hepatitis C virus (HCV) are unaware of their infection and are, therefore. potentially infectious to others. To enable effective case-finding policies to be developed, an understanding of where people, and injecting drug users (IDUs) in particular, are accessing HCV antibody testing is needed. HCV antibody testing data were collected electronically from 21 sentinel laboratories in England between 2002 and 2006 in this cross-sectional study. Service types of the physician requesting the HCV test were identified and classified. Differences in people being tested in each service type and over time were investigated. Over half a million people were tested in 5 years. Whilst most testing took place in hospital, a large proportion of people were tested in community care, particularly in general practice surgeries and genito-urinary medicine clinics. Younger people were more likely to be tested in community care, and there was evidence that testing differed according to ethnic status. IDUs were tested in all parts of the health services, although the highest proportion positive were from prisons and specialist services for drug users. Testing increased between 2002 and 2005 whilst the proportion of people testing positive declined. Routine laboratory data can provide valuable information on where people are being tested for HCV. Risk exposures should be investigated and testing targeted to people at higher risk for infection. Local laboratories should review data on testing locations and proportion positive to inform local initiatives to improve testing and yield.

Quantifying hepatitis C transmission risk using a new weighted scoring system for the Blood-Borne Virus Transmission Risk Assessment Questionnaire (BBV-TRAQ): applications for community-based HCV surveillance, education and prevention

Background

The hepatitis C virus (HCV) is a major cause of drug-related morbidity and mortality, with incidence data implicating a wide range of HCV transmission risk practices. The Blood-Borne Virus Transmission Risk Assessment Questionnaire (BBV-TRAQ) is a content valid instrument that comprehensively assesses HCV risk practices. This study examines the properties of a new weighted BBV-TRAQ designed to quantify HCV transmission risk among injecting drug users (IDU).

Methods

Analyses of cross-sectional surveys of Australian IDU (N = 450) were used to generate normative data and explore the properties of a weighted BBV-TRAQ. Items weights were assigned according to expert key informant ratings of HCV risk practices performed during the development stages of the BBV-TRAQ. A range of item weights was tested and psychometric properties explored. A weighting scheme was recommended based on the plausibility of normative subscale data in relation to research evidence and the ability of BBV-TRAQ scores to discriminate between HCV positive and negative participants.

Results

While retaining the psychometric properties of the unweighted scale and demonstrating good internal reliability. By taking into account the relative transmission risk of a broad range of putative HCV practices, the weighted BBV-TRAQ produced promising predictive validity results among IDU based on self-report HCV status, particularly among young and less experienced injectors.

Conclusion

Brief, easy to administer and score, and inexpensive to apply, the utility of the BBV-TRAQ for community based education and prevention is enhanced by the application of item weights, potentially offering a valid surrogate measure for HCV infection among IDU.

Prevalence and determinants of hepatitis C virus infection among female drug injecting sex workers in Glasgow

Background

Few studies of the prevalence of hepatitis C virus (HCV) infection have focussed on women who work as street sex workers to finance their drug use.

Methods

The investigators report the survey findings of such a population in Glasgow. All women attending the health and social care drop-in centre, situated in Glasgow's "Red Light Area", during a four-week period in 1999 were invited to participate in a survey involving the provision of a saliva sample for anonymous HCV testing and the self-completion of a questionnaire seeking demographic, sexual and injecting practice data.

Results

Of the 223 women who attended, 51% agreed to participate. Of the 98 women who provided a sufficient saliva sample, 64% (95% CI: 54%–74%) tested HCV antibody positive; 98% of those who tested positive had ever injected drugs. Adjusting for the 85% sensitivity of the saliva test, the HCV antibody prevalence among IDU sex workers sampled was 81%; a rate which is considerably higher than those recorded, contemporaneously, among Glasgow IDUs generally. Two factors were independently associated with HCV antibody positivity in saliva: ever shared needles and syringes (adjusted OR 5.7, 95% CI 2–16) and number of times imprisoned (adjusted OR 7.3, 95% CI 1.4–39, for more than five times compared to zero times).

Conclusion

Women who engage in street sex work to finance their drug habit are a particularly desperate, chaotic and vulnerable population. This study demonstrates that their HCV infection risk may be greater than that for other IDUs. Those responsible for designing interventions to prevent HCV infection among IDUs should consider the special needs of this group.

The changing epidemiology of hepatitis C virus infection in Europe

The epidemic of hepatitis C virus (HCV) infection in Europe is continuously evolving and epidemiological parameters (prevalence, incidence, disease transmission patterns and genotype distribution) have changed substantially during the last 15 years. Four main factors contribute to such changes: increased blood transfusion safety, improvement of healthcare conditions, continuous expansion of intravenous drug use and immigration to Europe from endemic areas. As a result, intravenous drug use has become the main risk factor for HCV transmission, prevalent infections have increased and genotype distribution has changed and diversified. Hence, prevalence data from studies conducted a decade ago may not be useful to estimate the current and future burden of HCV infection and additional epidemiological studies should be conducted, as well as new preventive strategies implemented to control the silent epidemic. This review summarizes recently published data on the epidemiology of HCV infection in Europe focusing on the factors currently shaping the epidemic.

Testing strategy to identify cases of acute hepatitis C virus (HCV) infection and to project HCV incidence rates

Surveillance for hepatitis C virus (HCV) is limited by the challenge of differentiating between acute and chronic infections. In this study, we evaluate a cross-sectional testing strategy that identifies individuals with acute HCV infection and we estimate HCV incidence. Anti-HCV-negative persons from four populations with various risks, i.e., blood donors, Veterans Administration (VA) patients, young injection drug users (IDU), and older IDU, were screened for HCV RNA by minipool or individual sample nucleic acid testing (NAT). The number of detected viremic seronegative infections was combined with the duration of the preseroconversion NAT-positive window period (derived from analysis of frequent serial samples from plasma donors followed from NAT detection to seroconversion) to estimate annual HCV incidence rates. Projected incidence rates were compared to observed incidence rates. Projected HCV incidence rates per 100 person-years were 0.0042 (95% confidence interval [95% CI], 0.0025 to 0.007) for blood donors, 0.86 (95% CI, 0.02 to 0.71) for VA patients, 39.8 (95% CI, 25.9 to 53.7) for young IDU, and 53.7 (95% CI, 23.4 to 108.8) for older IDU. Projected rates were most similar to observed incidence rates for young IDU (33.4; 95% CI, 28.0 to 39.9). This study demonstrates the value of applying a cross-sectional screening strategy to detect acute HCV infections and to estimate HCV incidence.

Prevalence and correlates of indirect sharing practices among young adult injection drug users in five U.S. cities

BACKGROUND

Sharing of drug paraphernalia to prepare, measure and divide drugs for injection remains an important residual risk factor for hepatitis C and other blood-borne infections among injection drug users (IDUs) especially as sharing of syringes for injection decreases.

METHODS

We analyzed data from five U.S. cities to determine the prevalence and independent correlates of non-syringe paraphernalia-sharing (NSPS) and syringe-mediated drug-splitting (SMDS) among 15-30-year-old IDUs who reported not injecting with others' used syringes (receptive syringe-sharing, RSS).

RESULTS

NSPS was reported by 54% of IDUs who did not practice RSS and was independently associated (p<0.05) with having > or =5 injection partners, injecting with sex partners or regular injection partners, injecting in shooting galleries, peers' sharing behaviors, lower self-efficacy for avoiding NSPS, and less knowledge of HIV and HCV transmission. SMDS was reported by 26% of IDUs who did not practice RSS, and was independently associated with having > or =5 injection partners, injecting in shooting galleries, and inversely associated with unknown HIV status.

CONCLUSIONS

NSPS and SMDS were common among young adult IDUs. Increased efforts to prevent these risky practices should address social and environmental contexts of injection and incorporate knowledge and skills building, self-efficacy, and peer norms.

Pilot of non-invasive (oral fluid) testing for HIV within a clinical setting

BACKGROUND

The objectives of the present study were: to determine the sensitivity and specificity of oral fluid testing compared with the performance of standard blood-based HIV enzyme immunoassay; to assess the feasibility of oral fluid specimen collection from clients for the purposes of HIV testing within a clinical setting; and to assess the clinical and laboratory impact regarding staffing, material resources, expertise and funding of oral fluid testing.

METHODS

A parallel comparative trial of oral fluid and blood testing was conducted among a group of HIV positive clients and a group of unknown HIV serostatus clients where each client was offered both tests. An ambulatory HIV clinic recruited 175 known HIV positive clients and 179 persons were recruited through an inner city sexual health clinic while attending for routine sexual health checks. Client responses to oral fluid collection were assessed. The sensitivity and specificity of oral fluid testing were calculated.

RESULTS

Of the 176 confirmed HIV reactive blood test results, the OraSure (OraSure Technologies, Beaverton, OR, USA) assay failed to detect only one of these, demonstrating a sensitivity of 99.4%. Of the 178 blood specimens that were tested as non-reactive by the AxSYM (Abbott Laboratories, Abbott Park, IL, USA) Combo system, OraSure recorded four of the corresponding oral fluid specimens as reactive (assumed to be false-positive), giving a specificity of 97.6%. Although evaluation of patients undergoing the test showed a large proportion (88.6%) preferred the OraSure test to conventional blood testing, a large minority of these (22.6%) made such a preference conditional on the OraSure test being as reliable as current blood testing.

CONCLUSIONS

This limited clinic based trial of oral fluid testing for HIV antibodies among an outpatient population has demonstrated the potential of oral fluid as a specimen for HIV testing. However, the lower performance of the test compared with current serum-based tests may limit the usefulness of OraSure to epidemiological studies or as an alternative screening tool in outreach settings among higher risk populations.

Hepatitis C virus (HCV) prevalence, and injecting risk behaviour in multiple sites in England in 2004

We sought to corroborate geographical differences in hepatitis C virus (HCV) prevalence and assess whether these can be explained by differences in injecting risk behaviour. A community recruited interview survey of 1058 injecting drug users (IDU) - including a blood spot specimen for antibody testing - was undertaken in seven cities in England. HCV prevalence varied from 27% to 74% across sites (chi(2)(6) = 115.3, P < 0.001). There was a significant variation in crack-injection, prison history, injecting frequency, homelessness, groin injecting, syringe reuse and sharing between the sites. Adjustment for clustering by site and other covariates attenuated the odds ratios (OR) for most variables: e.g. crack injection changed from an unadjusted OR of >2 to an adjusted OR of 1.4 (95% CI 0.9-2.0). Remaining significant covariates included: homelessness (OR 2.2; 1.4-3.6); ever imprisonment (OR 1.7; 1.2-2.5); syringe sharing >18 months ago (OR 2.0; 1.3-3.0); injecting duration and age. Introducing site as a second level variable did not reach significance (P = 0.10). HCV prevalence among IDU reporting 'never sharing' was 48%. Geographical variation in HCV prevalence remains poorly explained, but should be the key focus of our surveillance effort. Measures of sharing and their interpretation require greater scrutiny.

Modelling the impact on Hepatitis C transmission of reducing syringe sharing: London case study

BACKGROUND

Hepatitis C virus (HCV) prevalence and incidence among injecting drug users (IDUs) has increased in London and rest of UK. To inform public health action, mathematical modelling is used to explore the possible impact of strategies to decrease syringe sharing.

METHODS

A mathematical model was developed to simulate HCV transmission amongst IDUs in London. Because of parameter uncertainty, numerical search algorithms were used to obtain different model fits to HCV seroprevalence data from London for 2002-03. These simulations were used to explore the likely impact of HCV prevention activities that reduce syringe sharing amongst all IDUs, IDUs that have injected for greater than one year, or IDUs with lower or higher frequencies of syringe sharing.

RESULTS

Key differences between model fits centred on how they simulated the high HCV incidence amongst new injectors, either through assuming increased HCV infectivity during acute infection, a large sub-group of high frequency syringe sharers, or increased sharing among new IDUs. Despite parameter uncertainty, the model projections suggest that modest reductions in syringe sharing frequency (<25%) will reduce the HCV seroprevalence in newly initiated IDUs (injecting less than four years) but much larger and sustained reductions (>50%) are required to reduce the HCV seroprevalence in long-term IDUs (injecting more than 8 years). Critically the model also suggested that large reductions in HCV seroprevalence will be achieved only if interventions target all IDUs and reach IDUs within 12 months of injecting.

DISCUSSION

Public health interventions must reduce syringe sharing amongst all IDUs, including newly initiated IDUs, and be sustained for many years to reduce HCV infection. More accurate data on key behavioural (sharing frequency) and biological (percentage of infected IDUs that clear infection) parameters is required to improve model projections.

Sentinel laboratory surveillance of hepatitis C antibody testing in England: understanding the epidemiology of HCV infection

This paper describes sentinel laboratory surveillance of hepatitis C antibody testing in England. Demographic and test result data were supplemented by follow-up questionnaires sent to the requesting clinician. Between October 2002 and September 2003 almost 75000 anti-HCV tests were performed in eight sentinel centres. More males were tested than females and over half of those tested were aged 25-44 years. Overall 5.7% (3333/58144, range 2.8-7.7%) individuals tested positive. Follow-up questionnaire data showed that 82% (1043/1277) of the positives had injecting drug use reported as the main risk exposure. The majority of negative individuals were undergoing routine screening as recommended for specific patient groups. Most individuals were asymptomatic. Antibody prevalence was estimated to be 34% in current injecting drug users and 42% in former injectors. Comparing positives to routine national surveillance suggests that only 53% (1782/3333) of diagnosed cases were reported. Sentinel laboratory data can provide valuable supplementary data to national surveillance.