Examining trends in the incidence of HIV infection among people with a history of drug use to inform an outbreak investigation and response: A retrospective cohort study.

BACKGROUND: In the context of an outbreak of HIV among people who inject drugs in Glasgow, Scotland, identified in 2015, our objectives were to: (1) develop epidemiological methods to estimate HIV incidence using data linkage, and (2) examine temporal changes in HIV incidence to inform public health responses. METHODS: This was a retrospective cohort study involving data linkage of laboratory HIV testing data to identify individuals with a history of drug use. Person-years (PY) and Poisson regression were used to estimate incidence by time period (pre-outbreak: 2000-2010 and 2011-2013; early outbreak: 2014-2016; ongoing outbreak: 2017-2019). RESULTS: Among 13 484 individuals tested for HIV, 144 incident HIV infections were observed from 2000 to 2019. Incidence rates increased from pre-outbreak periods (1.00/1000 PY (95% confidence interval, CI: 0.60-1.65) in 2000-2010 and 1.70/1000 PY (95% CI: 1.14-2.54) in 2011-2013) to 3.02/1000 PY (95% CI: 2.36-3.86) early outbreak (2014-2016) and 2.35 (95% CI 1.74-3.18) during the ongoing outbreak period (2017-2019). Compared with the pre-outbreak period (2000-2010), the incidence rates were significantly elevated during both the early outbreak (2014-16) (adjusted incidence rate ratio (aIRR) = 2.87, 95% CI: 1.62-5.09, p < 0.001) and the ongoing outbreak periods (2017-19) (aIRR = 2.12, 95% CI: 1.16-3.90, p = 0.015). CONCLUSIONS: Public health responses helped to curb the rising incidence of HIV infection among people with a history of drug use in Glasgow, but further efforts are needed to reduce it to levels observed prior to the outbreak. Data linkage of routine diagnostic test data to assess and monitor incidence of HIV infection provided enhanced surveillance, which is important to inform outbreak investigations and guide national strategies on elimination of HIV transmission.

Impact of the COVID-19 Pandemic on HIV Test Uptake Among People Who Inject Drugs in the Context of an HIV Outbreak.

Glasgow, Scotland's largest city, has been experiencing an HIV outbreak among people who inject drugs (PWID) since 2015. A key focus of the public health response has been to increase HIV testing among those at risk of infection. Our aim was to assess the impact of COVID-19 on HIV testing among PWID in Glasgow. HIV test uptake in the last 12 months was quantified among: (1) PWID recruited in six Needle Exchange Surveillance Initiative (NESI) surveys (n = 6110); linked laboratory data for (2) people prescribed opioid agonist therapy (OAT) (n = 14,527) and (3) people hospitalised for an injecting-related hospital admission (IRHA) (n = 12,621) across four time periods: pre-outbreak (2010-2014); early-outbreak (2015-2016); ongoing-outbreak (2017-2019); and COVID-19 (2020-June 21). From the pre to ongoing period, HIV testing increased: the highest among people recruited in NESI (from 28% to 56%) and on OAT (from 17% to 54%) while the lowest was among people with an IRHA (from 15% to 42%). From the ongoing to the COVID-19 period, HIV testing decreased markedly among people prescribed OAT, from 54% to 37% (aOR 0.50, 95% CI 0.48-0.53), but increased marginally among people with an IRHA from 42% to 47% (aOR 1.19, 95% CI 1.08-1.31). In conclusion, progress in increasing testing in response to the HIV outbreak has been eroded by COVID-19. Adoption of a linked data approach could be warranted in other settings to inform efforts to eliminate HIV transmission.

Population-level estimates of hepatitis C reinfection post scale-up of direct-acting antivirals among people who inject drugs.

BACKGROUND & AIMS: Scale-up of highly effective direct-acting antivirals (DAAs) for HCV among people who inject drugs (PWID) in Scotland has led to a reduction in the prevalence of viraemia in this population. However, the extent of reinfection among those treated with DAAs remains uncertain. We estimated HCV reinfection rates among PWID in Scotland by treatment setting, pre- and post-introduction of DAAs, and the potential number of undiagnosed reinfections resulting from incomplete follow-up testing. METHODS: Through linkage of national clinical and laboratory HCV data, a retrospective cohort of PWID who commenced treatment between 2000-2018 and achieved a sustained virological response (SVR) were followed up for reinfection to December 2019. Reinfection was defined as a positive HCV antigen or RNA test. RESULTS: Of 5,686 SVRs among 5,592 PWID, 4,126 (73%) had an HCV RNA or antigen test post-SVR. Of those retested, we identified 361 reinfections (3.9/100 person-years [PY]). The reinfection rate increased from 1.5/100 PY among PWID treated in 2000-2009 to 8.8/100 PY in 2017-2018. The highest reinfection rates were observed among those treated in prison (14.3/100 PY) and community settings (9.5/100 PY). Among those treated in the DAA era (2015-2018), 68% were tested within the first year post-SVR but only 30% in the second year; while 169 reinfections were diagnosed in follow-up, an estimated 200 reinfections (54% of the estimated total) had gone undetected. CONCLUSIONS: HCV reinfection rates among PWID in Scotland have risen alongside the scale-up of DAAs and broadened access to treatment for those at highest risk, through delivery in community drug services. Promotion of HCV testing post-SVR among PWID is essential to ensure those reinfected are identified and retreated promptly. LAY SUMMARY: Increased rates of hepatitis C reinfection in Scotland were observed following the rapid scale-up of highly effective direct-acting antiviral (DAA) treatments among people who inject drugs. This demonstrates that community-based treatment pathways are reaching high-risk groups, regarded vital in efforts to eliminate the virus. However, we estimate that less than half of reinfections have been detected in the DAA era because of inadequate levels of retesting beyond the first year following successful treatment. Sustained efforts that involve high coverage of harm reduction measures and high uptake of annual testing are required to ensure prompt diagnosis and treatment of those reinfected if the goals of elimination are to be met.

Severe Acute Respiratory Syndrome Coronavirus 2 Serosurveillance in a Patient Population Reveals Differences in Virus Exposure and Antibody-Mediated Immunity According to Host Demography and Healthcare Setting.

Identifying drivers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure and quantifying population immunity is crucial to prepare for future epidemics. We performed a serial cross-sectional serosurvey throughout the first pandemic wave among patients from the largest health board in Scotland. Screening of 7480 patient serum samples showed a weekly seroprevalence ranging from 0.10% to 8.23% in primary and 0.21% to 17.44% in secondary care, respectively. Neutralization assays showed that highly neutralizing antibodies developed in about half of individuals who tested positive with enzyme-linked immunosorbent assay, mainly among secondary care patients. We estimated the individual probability of SARS-CoV-2 exposure and quantified associated risk factors. We show that secondary care patients, male patients, and 45-64-year-olds exhibit a higher probability of being seropositive. The identification of risk factors and the differences in virus neutralization activity between patient populations provided insights into the patterns of virus exposure during the first pandemic wave and shed light on what to expect in future waves.

Recent and Rapid Transmission of HIV Among People Who Inject Drugs in Scotland Revealed Through Phylogenetic Analysis.

Background: Harm reduction has dramatically reduced HIV incidence among people who inject drugs (PWID). In Glasgow, Scotland, <10 infections/year have been diagnosed among PWID since the mid-1990s. However, in 2015 a sharp rise in diagnoses was noted among PWID; many were subtype C with 2 identical drug-resistant mutations and some displayed low avidity, suggesting the infections were linked and recent. Methods: We collected Scottish pol sequences and identified closely related sequences from public databases. Genetic linkage was ascertained among 228 Scottish, 1820 UK, and 524 global sequences. The outbreak cluster was extracted to estimate epidemic parameters. Results: All 104 outbreak sequences originated from Scotland and contained E138A and V179E. Mean genetic distance was <1% and mean time between transmissions was 6.7 months. The average number of onward transmissions consistently exceeded 1, indicating that spread was ongoing. Conclusions: In contrast to other recent HIV outbreaks among PWID, harm reduction services were not clearly reduced in Scotland. Nonetheless, the high proportion of individuals with a history of homelessness (45%) suggests that services were inadequate for those in precarious living situations. The high prevalence of hepatitis C (>90%) is indicative of sharing of injecting equipment. Monitoring the epidemic phylogenetically in real time may accelerate public health action.

HCV avidity as a tool for detection of recent HCV infection: Sensitivity depends on HCV genotype.

Accurate detection of incident hepatitis C virus (HCV) infection is required to target and evaluate public health interventions, but acute infection is largely asymptomatic and difficult to detect using traditional methods. Our aim was to evaluate a previously developed HCV avidity assay to distinguish acute from chronic HCV infection. Plasma samples collected from recent seroconversion subjects in two large Australian cohorts were tested using the avidity assay, and the avidity index (AI) was calculated. Demographic and clinical characteristics of patients with low/high AI were compared via logistic regression. Sensitivity and specificity of the assay for recent infection and the mean duration of recent infection (MDRI) were estimated stratified by HCV genotype. Avidity was assessed in 567 samples (from 215 participants), including 304 with viraemia (defined as ≥250 IU/mL). An inverse relationship between AI and infection duration was found in viraemic samples only. The adjusted odds of a low AI (<30%) decreased with infection duration (odds ratio [OR] per week of 0.93; 95% CI:0.89-0.97), and were lower for G1 compared with G3 samples (OR = 0.14; 95% CI:0.05-0.39). Defining recent infection as <26 weeks, sensitivity (at AI cut-off of 20%) was estimated at 48% (95% CI:39-56%), 36% (95% CI:20-52%), and 65% (95% CI:54-75%) and MDRI was 116, 83, and 152 days for all genotypes, G1, and G3, respectively. Specificity (≥52 weeks infection duration, all genotypes) was 96% (95% CI:90-98%). HCV avidity testing has utility for detecting recent HCV infection in patients, and for assessing progress in reaching incidence targets for eliminating transmission, but variation in assay performance across genotype should be recognized.

Needle syringe programmes and opioid substitution therapy for preventing hepatitis C transmission in people who inject drugs.

BACKGROUND: Needle syringe programmes and opioid substitution therapy for preventing hepatitis C transmission in people who inject drugsNeedle syringe programmes (NSP) and opioid substitution therapy (OST) are the primary interventions to reduce hepatitis C (HCV) transmission in people who inject drugs. There is good evidence for the effectiveness of NSP and OST in reducing injecting risk behaviour and increasing evidence for the effectiveness of OST and NSP in reducing HIV acquisition risk, but the evidence on the effectiveness of NSP and OST for preventing HCV acquisition is weak. OBJECTIVES: To assess the effects of needle syringe programmes and opioid substitution therapy, alone or in combination, for preventing acquisition of HCV in people who inject drugs. SEARCH METHODS: We searched the Cochrane Drug and Alcohol Register, CENTRAL, the Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA), the NHS Economic Evaluation Database (NHSEED), MEDLINE, Embase, PsycINFO, Global Health, CINAHL, and the Web of Science up to 16 November 2015. We updated this search in March 2017, but we have not incorporated these results into the review yet. Where observational studies did not report any outcome measure, we asked authors to provide unpublished data. We searched publications of key international agencies and conference abstracts. We reviewed reference lists of all included articles and topic-related systematic reviews for eligible papers. SELECTION CRITERIA: We included prospective and retrospective cohort studies, cross-sectional surveys, case-control studies and randomised controlled trials that measured exposure to NSP and/or OST against no intervention or a reduced exposure and reported HCV incidence as an outcome in people who inject drugs. We defined interventions as current OST (within previous 6 months), lifetime use of OST and high NSP coverage (regular attendance at an NSP or all injections covered by a new needle/syringe) or low NSP coverage (irregular attendance at an NSP or less than 100% of injections covered by a new needle/syringe) compared with no intervention or reduced exposure. DATA COLLECTION AND ANALYSIS: We followed the standard Cochrane methodological procedures incorporating new methods for classifying risk of bias for observational studies. We described study methods against the following 'Risk of bias' domains: confounding, selection bias, measurement of interventions, departures from intervention, missing data, measurement of outcomes, selection of reported results; and we assigned a judgment (low, moderate, serious, critical, unclear) for each criterion. MAIN RESULTS: We identified 28 studies (21 published, 7 unpublished): 13 from North America, 5 from the UK, 4 from continental Europe, 5 from Australia and 1 from China, comprising 1817 incident HCV infections and 8806.95 person-years of follow-up. HCV incidence ranged from 0.09 cases to 42 cases per 100 person-years across the studies. We judged only two studies to be at moderate overall risk of bias, while 17 were at serious risk and 7 were at critical risk; for two unpublished datasets there was insufficient information to assess bias. As none of the intervention effects were generated from RCT evidence, we typically categorised quality as low. We found evidence that current OST reduces the risk of HCV acquisition by 50% (risk ratio (RR) 0.50, 95% confidence interval (CI) 0.40 to 0.63, I2 = 0%, 12 studies across all regions, N = 6361), but the quality of the evidence was low. The intervention effect remained significant in sensitivity analyses that excluded unpublished datasets and papers judged to be at critical risk of bias. We found evidence of differential impact by proportion of female participants in the sample, but not geographical region of study, the main drug used, or history of homelessness or imprisonment among study samples.Overall, we found very low-quality evidence that high NSP coverage did not reduce risk of HCV acquisition (RR 0.79, 95% CI 0.39 to 1.61) with high heterogeneity (I2 = 77%) based on five studies from North America and Europe involving 3530 participants. After stratification by region, high NSP coverage in Europe was associated with a 76% reduction in HCV acquisition risk (RR 0.24, 95% CI 0.09 to 0.62) with less heterogeneity (I2 =0%). We found low-quality evidence of the impact of combined high coverage of NSP and OST, from three studies involving 3241 participants, resulting in a 74% reduction in the risk of HCV acquisition (RR 0.26 95% CI 0.07 to 0.89). AUTHORS' CONCLUSIONS: OST is associated with a reduction in the risk of HCV acquisition, which is strengthened in studies that assess the combination of OST and NSP. There was greater heterogeneity between studies and weaker evidence for the impact of NSP on HCV acquisition. High NSP coverage was associated with a reduction in the risk of HCV acquisition in studies in Europe.

HCV epidemiology in high-risk groups and the risk of reinfection.

Injecting risk behaviours among people who inject drugs (PWID) and high-risk sexual practices among men who have sex with men (MSM) are important routes of hepatitis C virus (HCV) transmission. Current direct-acting antiviral treatment offers unique opportunities for reductions in HCV-related liver disease burden and epidemic control in high-risk groups, but these prospects could be counteracted by HCV reinfection due to on-going risk behaviours after successful treatment. Based on existing data from small and heterogeneous studies of interferon-based treatment, the incidence of reinfection after sustained virological response range from 2-6/100 person years among PWID to 10-15/100 person years among human immunodeficiency virus-infected MSM. These differences mainly reflect heterogeneity in study populations with regards to risk behaviours, but also reflect variations in study designs and applied virological methods. Increasing levels of reinfection are to be expected as we enter the interferon-free treatment era. Individual- and population-level efforts to address and prevent reinfection should therefore be undertaken when providing HCV care for people with on-going risk behaviour. Constructive strategies include acknowledgement, education and counselling, harm reduction optimization, scaled-up treatment including treatment of injecting networks, post-treatment screening, and rapid retreatment of reinfections.

Effectiveness of needle/syringe programmes and opiate substitution therapy in preventing HCV transmission among people who inject drugs.

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the impact of needle/syringe programmes with and without opiate substitution therapy (OST) on the incidence of HCV infection among people who inject drugs (PWID).To assess the effect of OST alone on the incidence of HCV infection among PWID. RESEARCH QUESTIONS: How effective are needle/syringe programmes (NSP) with and without the use of OST for reducing HCV incidence among PWID?How effective is OST alone for reducing HCV incidence among PWID?How does the effect of NSP and OST vary according to duration of treatment (i.e. for NSPs weekly attendance versus monthly)?How does the effect of NSP vary according to the type of service (fixed site versus mobile; high coverage versus low coverage)?How does the effect of OST vary according to the dosage of OST, type of substitution used and adherence to treatment?

SARS-CoV-2 vaccine uptake and risks of severe COVID-19 disease among people prescribed opioid agonist therapy in Scotland.

BACKGROUND: There is limited evidence quantifying the risk of severe COVID-19 disease among people with opioid dependence. We examined vaccine uptake and severe disease (admission to critical care or death with COVID-19) among individuals prescribed opioid agonist therapy (OAT). METHOD: A case-control design was used to examine vaccine uptake in those prescribed OAT compared with the general population, and the association between severe disease and OAT. In both analyses, 10 controls from the general population were matched (to each OAT recipient and COVID-19 case, respectively) according to socio-demographic factors. Conditional logistic regression was used to estimate rate ratios (RR) for severe disease. RESULTS: Vaccine uptake was markedly lower in the OAT cohort (dose 1: 67%, dose 2: 53% and dose 3: 31%) compared with matched controls (76%, 72% and 57%, respectively). Those prescribed OAT within the last 5 years, compared with those not prescribed, had increased risk of severe COVID-19 (RR 3.38, 95% CI 2.75 to 4.15), particularly in the fourth wave (RR 6.58, 95% CI 4.20 to 10.32); adjustment for comorbidity and vaccine status attenuated this risk (adjusted RR (aRR) 2.43, 95% CI 1.95 to 3.02; wave 4 aRR 3.78, 95% CI 2.30 to 6.20). Increased risk was also observed for those prescribed OAT previously (>3 months ago) compared with recently (aRR 1.74, 95% CI 1.11 to 2.71). CONCLUSIONS: The widening gap in vaccine coverage for those prescribed OAT, compared with the general population, is likely to have exacerbated the risk of severe COVID-19 in this population over the pandemic. However, continued OAT use may have provided protection from severe COVID-19 among those with opioid dependence.

Risk of drug-related death associated with co-prescribing of gabapentinoids and Z-drugs among people receiving opioid-agonist treatment: A national retrospective cohort study.

BACKGROUND: Prescribing of gabapentinoids and Z-drug-hypnotics has increased in the population and among people receiving opioid-agonist treatment (OAT) for opioid dependence. Evidence is mixed on whether co-prescribing of sedatives such as gabapentinoids and Z-drugs during OAT increases risk of drug-related death (DRD). METHODS: We conducted a retrospective cohort study of individuals prescribed OAT between 2011 and 2020 in Scotland. Prescribing records were linked to mortality data and other healthcare datasets (sociodemographic, comorbidity). We identified episodes of treatment with gabapentinoids/Z-drugs and used multivariable quasi-Poisson regression to model associations between co-prescription and DRD risk. RESULTS: Among 46,602 individuals with 304,783 person-years of follow-up, we found that co-prescription was common, with 25 % and 34 % ever being co-prescribed gabapentinoids and Z-drugs, respectively. Gabapentinoid exposure was strongly associated (adjusted hazard ratio (aHR)=2·18, 95 % CI=1·92, 2·46) and Z-drug exposure moderately associated (aHR=1·39, 95 % CI=1·15, 1·66) with elevated risk of DRD. Gabapentinoid exposure was associated with DRD risk on and off OAT; Z-drug exposure was less strongly associated with DRD risk when on OAT. CONCLUSIONS: Co-prescription of gabapentinoids and Z-drugs is common among OAT patients. However, co-prescription is associated with increased risk of DRD. Alternatives to prescribing sedative medications to OAT patients and/or greater monitoring - if prescribed - are needed.

Factors associated with SARS-CoV-2 testing, diagnosis and COVID-19 disease among individuals prescribed opioid-agonist treatment: a nationwide retrospective cohort study.

OBJECTIVES: Among people receiving opioid-agonist treatment (OAT), the risk of COVID-19 infection and disease may be higher owing to underlying health problems and vulnerable social circumstances. We aimed to determine whether recent OAT, when compared with past exposure, affected the risk of (i) testing for SARS-CoV-2, (ii) testing positive for SARS-CoV-2, and (iii) being hospitalized or dying with COVID-19 disease. METHODS: We included individuals prescribed OAT in Scotland from 2015 to 2020. We performed record linkage to SARS-CoV-2 PCR testing, vaccination, hospitalization, and mortality data, and followed up from March 2020 to December 2021. We used proportional hazards analysis and multivariate logistic regression to estimate associations between recent OAT prescription (in the previous 2 months), compared with past exposure (off treatment for over a year), and COVID-19 outcomes. Models were adjusted for confounders. RESULTS: Among 36 093 individuals prescribed OAT, 19 071 (52.9%) were tested for SARS-CoV-2; 2896 (8.3%) tested positive; and 552 (1.5%) were hospitalized or died with COVID-19. Recent OAT, compared with past exposure, was associated with lower odds of testing positive among those tested (aOR, 0.63; 95% CI, 0.57-0.69). However, among those testing positive, recent OAT was associated with two-fold higher odds of hospitalization or death (aOR, 2.04; 95% CI, 1.60-2.59). DISCUSSION: We found that recent OAT was associated with lower odds of SARS-CoV-2 infection, but with higher odds of disease once diagnosed. Clinical studies are needed to unravel the role of OAT in these associations. An enhanced effort is warranted to increase vaccine coverage among OAT patients to mitigate the severe consequences of COVID-19.

Evaluating the effect of direct-acting antiviral agent treatment scale-up on Hepatitis C virus prevalence among people who inject drugs in UK.

BACKGROUND: There is limited empirical work assessing the effectiveness of treatment as prevention (TasP) in reducing HCV prevalence among people who inject drugs (PWID). Here, we used survey data from the UK during 2010-2020, to evaluate the impact of direct-acting antiviral agent (DAA) treatment scale-up, which started in 2015, on HCV prevalence among PWID. METHODS: We fitted a logistic regression to time/location specific data on prevalence from the Needle Exchange Surveillance Initiative in Scotland and Unlinked Anonymous Monitoring programme in England. For each post-intervention year and location, we quantified the effect of TasP as the difference between estimated prevalence and its counterfactual (prevalence in the absence of scale-up). Progress to elimination was assessed by comparing most recent prevalence against one in 2015. RESULTS: In 2015, prevalence ranged from 0.44 to 0.71 across the 23 locations (3 Scottish, 20 English). Compared to counterfactuals, there was an absolute reduction of 46% (95% credible interval [32%,59%]) in Tayside in 2020, 35% ([24%,44%]) in Glasgow in 2019, and 25% ([10%,39%]) in the Rest of Scotland in 2020. The English sites with highest estimated absolute reductions in 2021 were South Yorkshire (45%, [29%,58%]), Thames Valley (49%, [34%,59%]) and West London (41%, [14%,59%]). Compared to 2015, there was 80% probability that prevalence had fallen by 65% in Tayside, 53% in Glasgow and 36% in the Rest of Scotland. The English sites with highest % prevalence decrease compared to 2015, achieved with probability 80%, were Chesire & Merseyside (70%), South Yorkshire (65%) and Thames Valley (71%). Higher treatment intensity was associated with higher reductions in prevalence. CONCLUSION: Conclusion. Real-world evidence showing substantial reductions in chronic HCV associated with increase of HCV treatment scale-up in the community thus supporting the effectiveness of HCV treatmen as prevention in people who inject drugs.

Association between antibody responses post-vaccination and severe COVID-19 outcomes in Scotland.

Several population-level studies have described individual clinical risk factors associated with suboptimal antibody responses following COVID-19 vaccination, but none have examined multimorbidity. Others have shown that suboptimal post-vaccination responses offer reduced protection to subsequent SARS-CoV-2 infection; however, the level of protection from COVID-19 hospitalisation/death remains unconfirmed. We use national Scottish datasets to investigate the association between multimorbidity and testing antibody-negative, examining the correlation between antibody levels and subsequent COVID-19 hospitalisation/death among double-vaccinated individuals. We found that individuals with multimorbidity ( ≥ five conditions) were more likely to test antibody-negative post-vaccination and 13.37 [6.05-29.53] times more likely to be hospitalised/die from COVID-19 than individuals without conditions. We also show a dose-dependent association between post-vaccination antibody levels and COVID-19 hospitalisation or death, with those with undetectable antibody levels at a significantly higher risk (HR 9.21 [95% CI 4.63-18.29]) of these serious outcomes compared to those with high antibody levels.

Infections with spore-forming bacteria in persons who inject drugs, 2000-2009.

Since 2000 in the United Kingdom, infections caused by spore-forming bacteria have been associated with increasing illness and death among persons who inject drugs (PWID). To assess temporal and geographic trends in these illnesses (botulism, tetanus, Clostridium novyi infection, and anthrax), we compared rates across England and Scotland for 2000-2009. Overall, 295 infections were reported: 1.45 per 1,000 PWID in England and 4.01 per 1,000 PWID in Scotland. The higher rate in Scotland was mainly attributable to C. novyi infection and anthrax; rates of botulism and tetanus were comparable in both countries. The temporal and geographic clustering of cases of C. novyi and anthrax into outbreaks suggests possible contamination of specific heroin batches; in contrast, the more sporadic nature of tetanus and botulism cases suggests that these spores might more commonly exist in the drug supply or local environment although at varying levels. PWID should be advised about treatment programs, injecting hygiene, risks, and vaccinations.

Decrease in health-related quality of life associated with awareness of hepatitis C virus infection among people who inject drugs in Scotland.

BACKGROUND & AIMS: Chronic hepatitis C virus (HCV) infection can significantly reduce health-related quality of life (QoL), but it is not clear if reduction is associated with the infection or with being aware of one's infection status. Understanding the impact of a HCV diagnosis on QoL is essential to inform decision-making regarding screening/testing and treatment. METHODS: Using a cross-sectional design, we assessed QoL in 2898 people who inject drugs (PWID), surveyed in Scotland during 2010 using EQ-5D. Multifactorial regression compared self-reported QoL between PWID who were (i) chronically HCV-infected and aware of their infected status, (ii) chronically HCV-infected but unaware, and (iii) not chronically infected. RESULTS: Median time since onset of injecting was 10years; not chronically infected PWID were younger and had shorter injecting careers than chronically infected PWID. Median EQ-5D was highest for the not chronically infected and the chronic/unaware groups (0.73) compared with the chronic/aware group (0.66). After adjustment for demographic and behavioural co-factors, QoL was significantly reduced in chronic/aware compared with chronic/unaware PWID (adjusted B=-0.09, p=0.005); there was no evidence for a difference in QoL between not chronically infected and chronic/unaware PWID (adjusted B=-0.03, p=0.13). CONCLUSIONS: Awareness of one's chronic HCV status was associated with reduced health-related QoL, but there was no evidence for further reduction attributable to chronic infection itself after adjusting for important covariate differences.

Improved health-related quality of life after hepatitis C viraemic clearance among people who inject drugs may not be durable.

BACKGROUND AND AIMS: Chronic infection with the hepatitis C virus (HCV) has a detrimental impact on health-related quality of life (QoL). Scale-up of HCV direct-acting antiviral (DAA) therapy among people who inject drugs (PWID) is underway in several countries since the introduction of interferon-free regimens. This study aimed to assess the impact of DAA treatment success on QoL for PWID. DESIGN: Cross-sectional study using two rounds of the Needle Exchange Surveillance Initiative, a national anonymous bio-behavioural survey and a longitudinal study involving PWID who underwent DAA therapy. SETTING: The setting for the cross-sectional study was Scotland (2017-2018, 2019-2020). The setting for the longitudinal study was the Tayside region of Scotland (2019-2021). PARTICIPANTS: In the cross-sectional study PWID were recruited from services providing injecting equipment (n = 4009). In the longitudinal study, participants were PWID on DAA therapy (n = 83). MEASUREMENTS: In the cross-sectional study, the association between QoL (measured using the EQ-5D-5L quality of life instrument) and HCV diagnosis and treatment was assessed using multilevel linear regression. In the longitudinal study, QoL was compared at four timepoints using multilevel regression, from treatment commencement until 12 months following commencement. FINDINGS: In the cross-sectional study, 41% (n = 1618) were ever chronically HCV infected, of whom 78% (n = 1262) were aware of their status and of whom 64% (n = 704) had undergone DAA therapy. There was no evidence for a marked QoL improvement associated with viral clearance among those treated for HCV (B = 0.03; 95% CI, -0.03 to 0.09). In the longitudinal study, improved QoL was observed at the sustained virologic response test timepoint (B = 0.18; 95% CI, 0.10-0.27), but this was not maintained at 12 months following start of treatment (B = 0.02; 95% CI, -0.05 to 0.10). CONCLUSIONS: Successful direct-acting antiviral therapy for hepatitis C infection may not lead to a durable improvement in quality of life among people who inject drugs, although there may be a transient improvement around the time of sustained virologic response. Economic models of the impact of scaling-up treatment may need to include more conservative quality of life benefits over and above reductions in mortality, disease progression and transmission of infection.

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis.

BACKGROUND: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender. METHODS: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle-Ottawa scale. This study is registered with PROSPERO, CRD42020220884. FINDINGS: Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987-2021 for HIV and 1992-2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3-2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0-14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2-1·8; I2=66·9%) and HCV (1·5, 1·3-1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1-1·6; I2=55·3%) and HCV (1·2, 1·1-1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6-7), indicating moderate risk. INTERPRETATION: Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs. FUNDING: Canadian Institutes of Health Research, Fonds de recherche du Québec-Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO.

Anthrax infection among heroin users in Scotland during 2009-2010: a case-control study by linkage to a national drug treatment database.

Using a data-linkage approach, we conducted a case-control study to investigate risk factors in an outbreak of anthrax infection among Scottish heroin users. Factors associated with an increased risk of infection included longer injecting history, receiving opioid substitution therapy, and alcohol consumption. Smoking heroin was associated with lower risk of infection.