Estimate Hepatitis C Virus Incidence Research Articles

Hepatitis C incidence among patients attending primary care health services that specialise in the care of people who inject drugs, Victoria, Australia, 2009 to 2020.

Monitoring trends in hepatitis C virus (HCV) incidence is critical for evaluating strategies aimed at eliminating HCV as a public health threat. We estimate HCV incidence and assess trends in incidence over time among primary care patients. Data were routinely extracted, linked electronic medical records from 12 primary care health services. Patients included were aged ≥16 years, tested HCV antibody negative on their first test recorded and had at least one subsequent HCV antibody or RNA test (January 2009-December 2020). HCV incident infections were defined as a positive HCV antibody or RNA test. A generalised linear model assessed the association between HCV incidence and calendar year. In total, 6711 patients contributed 17,098 HCV test records, 210 incident HCV infections and 19,566 person-years; incidence was 1.1 per 100 person-years (95% confidence interval (CI): 0.9 to 1.2). Among 559 (8.2%) patients ever prescribed opioid-related pharmacotherapy (ORP) during the observation period, 135 infections occurred during 2,082 person-years (incidence rate of 6.5 per 100 person-years (95% CI: 5.4 to 7.7)). HCV incidence declined 2009-2020 overall (incidence rate ratio per calendar year 0.8 (95% CI: 0.8 to 0.9) and among patients ever prescribed ORT (incidence rate ratio per calendar year 0.9, 95% CI: 0.75 to 1.0). HCV incidence declined among patients at primary care health services including among patients ever prescribed ORP and during the period following increased access to DAA therapy.

Prevalence, estimated incidence, risk behaviours, and genotypic distribution of hepatitis C virus among people who inject drugs accessing harm-reduction services in Kenya: a retrospective cohort study

Sub-Saharan Africa has a large population of people with hepatitis C virus (HCV) infection, yet little is known about HCV among people who inject drugs this region. We assessed the prevalence of HCV mono-infection and HIV-HCV co-infection, and the estimated incidence, genotypes, and risk behaviours associated with HCV among people who inject drugs in Kenya. People aged 18 years or older who were living in Nairobi, coastal Kenya, or western Kenya, had a history of injection drug use, and had used any illicit drugs in the past 12 months were recruited at needle and syringe programme sites using respondent-driven sampling. Participants were screened for the presence of an anti-HCV antibody. Those who were anti-HCV positive underwent confirmatory HCV RNA testing, and those with detectable HCV RNA were genotyped. Participants were interviewed regarding parenteral risk behaviours and exposure to services received at the needle and syringe programme sites. We examined correlates of HCV infection and HIV-HCV co-infection using bivariate and multivariate regression, and estimated HCV incidence. Of 2188 enrolled participants, 291 (13%) were anti-HCV positive: 183 (22%) of 842 participants in coastal Kenya, 105 (13%) of 817 in Nairobi, and three (1%) of 529 in western Kenya. 284 anti-HCV-positive participants underwent successful HCV RNA testing, of whom 230 (81%) were viraemic. Estimated incidence rates of anti-HCV positivity per 100 person-years were 6·31 in coastal Kenya, 3·19 in Nairobi, and 0·22 in western Kenya. HCV incidence rate was greater in coastal Kenya compared with Nairobi (incidence rate ratio 1·97 [95% CI 1·35-2·93], p=0·0001) and the western region (28·17 [7·55-236·58], p<0·0001). In the coastal region, history of incarceration, more years injecting, more injections in the past month, and receptive cooker sharing were associated with increased risk of HCV, while female sex, more years injecting, more injections in the past month, and regular use of a syringe with a detachable needle were associated with HCV risk in Nairobi. HCV prevalence among HIV-positive participants was 50% (66 of 131 participants) in coastal Kenya, 35% (42 of 121) in Nairobi, and 4% (one of 23) in western Kenya. Risk factors for HIV-HCV co-infection were similar to those observed for HCV mono-infection. The prevailing genotypes were 1a (51%), 4a (47%), and mixed (2%; three 1a/4a and one 1a/2b). HCV prevalence, estimated incidence, and risk behaviours among people who inject drugs in Kenya vary with region, with the highest estimated incidence observed in coastal Kenya. These findings should be used to inform focused strategies to reduce HCV transmission, such as expansion of needle and syringe programmes, upscaling of opioid agonist therapy, and treatment as prevention in regions affected by injection drug use and HCV. National Institute on Drug Abuse.

Sexual behaviour as a risk factor for hepatitis C virus infection among people who inject drugs in Montreal, Canada.

Hepatitis C virus (HCV) acquisition remains high in key risk environments including injection drug use and sex between men. However, few studies examine the independent contribution of sexual behaviour to HCV acquisition among people who inject drugs (PWID). We estimated HCV incidence and examined sexual behaviour as a time-varying predictor of HCV acquisition in a prospective cohort study of PWID in Montreal (2004-2017). Initially, HCV-negative participants completed behavioural questionnaires and HCV antibody testing (6months until 2011, 3months thereafter). A time-updating exposure variable (no sex, opposite-sex partner only, ≥1 same-sex partner) was generated for the previous 6/3months. Time to HCV seroconversion was examined using Cox regression analysis, adjusted for age, unstable housing and incarceration (both past 3months), and daily, heroin, cocaine and prescription opioid injecting (all past month). Among 440 PWID (baseline: median age 33years, 18.9% female, 1.4% HIV-positive), 156 participants seroconverted during follow-up (overall incidence rate: 11.9/100 person-years [PY]). Incidence was lowest in the no sex group (8.70 and 2.91 cases/100 PY in males and females, respectively) and highest in the ≥1 same-sex partner group (24.14 and 21.97 cases/100 PY in males and females, respectively). Among males, HCV risk was 47% lower in those reporting no sex compared to ≥1 same-sex partner (adjusted hazard ratio: 0.53, 95% confidence interval: 0.28, 0.99). In this cohort of PWID, reporting recent same-sex partners was associated with greater risk of HCV acquisition among males, necessitating targeted harm reduction strategies that consider the complex interplay of sexual and injecting risk behaviours.

Hepatitis C virus infection in Argentina: Burden of chronic disease.

To estimate the progression of the hepatitis C virus (HCV) epidemic and measure the burden of HCV-related morbidity and mortality. Age- and gender-defined cohorts were used to follow the viremic population in Argentina and estimate HCV incidence, prevalence, hepatic complications, and mortality. The relative impact of two scenarios on HCV-related outcomes was assessed: (1) increased sustained virologic response (SVR); and (2) increased SVR and treatment. Under scenario 1, SVR raised to 85%-95% in 2016. Compared to the base case scenario, there was a 0.3% reduction in prevalent cases and liver-related deaths by 2030. Given low treatment rates, cases of hepatocellular carcinoma and decompensated cirrhosis decreased < 1%, in contrast to the base case in 2030. Under scenario 2, the same increases in SVR were modeled, with gradual increases in the annual diagnosed and treated populations. This scenario decreased prevalent infections 45%, liver-related deaths 55%, liver cancer cases 60%, and decompensated cirrhosis 55%, as compared to the base case by 2030. In Argentina, cases of end stage liver disease and liver-related deaths due to HCV are still growing, while its prevalence is decreasing. Increasing in SVR rates is not enough, and increasing in the number of patients diagnosed and candidates for treatment is needed to reduce the HCV disease burden. Based on this scenario, strategies to increase diagnosis and treatment uptake must be developed to reduce HCV burden in Argentina.

Incidence and prevalence of hepatitis c virus infection among persons who inject drugs in New York City: 2006–2013

BackgroundHepatitis C virus infection is a source of significant preventable morbidity and mortality among persons who inject drugs (PWID). We sought to assess trends in hepatitis C virus (HCV) infection among PWID from 2006 to 2013 in New York City (NYC). MethodsAnnual cross-sectional surveys of PWID entering a large drug abuse treatment program were performed. Risk behavior questionnaires were administered, and HIV and HCV testing were conducted. Comparisons were made with prior prevalence and incidence estimates in 1990–1991 and 2000–2001 reflecting different periods of combined prevention and treatment efforts. ResultsHCV prevalence among PWID (N: 1535) was 67% (95% CI: 66–70%) during the study period, and was not significantly different from that observed in 2000–2001. The estimated HCV incidence among new injectors (persons injecting for ≤6 years) during 2006–2013 was 19.5/100 PYO (95% CI: 17–23) and did not differ from that observed in 2000–2001 (18/100 PYO, 95% CI: 14–23/100). ConclusionsDespite the expansion of combined prevention programming between 2000–2001 and 2006–2013, HCV prevalence remained high. Estimated HCV incidence among new injectors also remained high, and not significantly lower than in 2000–2001, indicating that expanded combined prevention efforts are needed to control the HCV epidemic among PWID in NYC.

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus

We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion-transmitted risk at three large Brazilian blood centers. Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HCV. HBV and HCV prevalence rates were calculated for all first-time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors. There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti-HBc reactivity was 289 per 100,000 donations and of anti-HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77-7.03) per 100,000 person-years, and residual risk of HCV window-phase infections was estimated at 5.0 per million units transfused. Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.

Incidence of hepatitis C in drug injectors: the role of homelessness, opiate substitution treatment, equipment sharing, and community size

A prospective cohort study estimated the incidence of hepatitis C virus (HCV) in drug injectors in South Wales (UK). In total, 286/481 eligible seronegative individuals were followed up after approximately 12 months. Dried blood spot samples were collected and tested for anti-HCV antibody and behavioural data were collected at baseline and follow-up. HCV incidence was 5.9/100 person-years [95% confidence interval (CI) 3.4-9.5]. HCV incidence was predicted by community size [incident rate ratio (IRR) 6.6, 95% CI 2.11-20.51, P = 0.001], homelessness (IRR 2.9, 95% CI 1.02-8.28, P = 0.047) and sharing injecting equipment (IRR 12.7, 95% CI 1.62-99.6, P = 0.015). HCV incidence was reduced in individuals in opiate substitution treatment (IRR 0.34, 95% CI 0.12-0.99, P = 0.047). In order to reduce follow-up bias we used multiple imputation of missing data using switching regression; after imputation estimated HCV incidence was 8.5/100 person-years (95% CI 5.4-12.7). HCV incidence varies with community size, equipment sharing and homelessness are associated with increased HCV incidence and opiate substitution treatment may be protective against HCV.

Modelling and calibration of the hepatitis C epidemic in Australia

Hepatitis C virus (HCV) infection in Australia is predominantly transmitted through injecting drug use. A reduction in the heroin supply in Australia in late 2000 and early 2001 may have impacted the number of injecting drug users (IDUs) and the number of new hepatitis C infections. This paper updates estimates of HCV incidence between 1960 and 2005 and models long-term sequelae from infection. Outcomes among those with HCV were also recently assessed in a linkage study assessing cancer and causes of death following HCV diagnosis in New South Wales. Linkage study outcomes have been used here to calibrate modelled outcomes. Mathematical models were used to estimate HCV incidence among IDUs, migrants to Australia from high HCV-prevalence countries, and other HCV exposure groups. Recent trends in numbers of IDUs were based on indicators of injecting drug use. A natural history of HCV model was applied to estimate the prevalence of HCV in the population. Model predicted endpoints that were calibrated against the NSW linkage data over the period 1995-2002 were: (i) incident hepatocellular carcinoma (HCC); (ii) opioid overdose deaths; (iii) liver-related deaths; and (iv) all-cause mortality. Modelled estimates and the linkage data show reasonably good calibration for HCC cases and all-cause mortality. The estimated HCC incidence was increased from 70 cases in 1995 to 100 cases in 2002. All-cause mortality estimated at 1000 in 1995 increased to 1600 in 2002. Comparison of annual opioid deaths shows some agreement. However, the models underestimate the rate of increase observed between 1995 and 1999 and do not entirely capture the rapid decrease in overdose deaths from 2000 onwards. The linkage data showed a peak of overdose deaths at 430 in 1999 compared to 320 estimated by the models. Comparison of observed liver deaths with the modelled numbers showed poor agreement. A good agreement would require an increase in liver deaths from the assumed 2 to 5% per annum following cirrhosis in the models. Mathematical models suggest that HCV incidence decreased from a peak of 14,000 infections in 1999 to 9700 infections in 2005, largely attributable to a reduction in injecting drug use. The poor agreement between projected and linked liver deaths could reflect differing coding of causes of deaths, underestimates of the numbers of people with cirrhosis following HCV, or underestimates of rates of liver death following cirrhosis. The reasonably good agreement between most of the modelled estimates with observed linkage data provides some support for the assumptions used in the models.

Incidence and risk factors for hepatitis C infection in a cohort of women in rural Egypt

A prospective cohort study of the incidence and risk factors for hepatitis C virus (HCV) infection was performed in 2171 pregnant women in three rural Egyptian villages who were HCV antibody (anti-HCV) and RNA (HCV-RNA) negative at baseline. During an average of 2.2 years follow up, 25 incident cases were observed, giving an estimated HCV incidence of 5.2/1000 person-years (PY). The infection rate correlated with community anti-HCV prevalence in pregnant women, while the perinatal incidence rate of 11.2/1000 PY was almost five times that of the non-perinatal rate (2.3/1000 PY). The data suggested iatrogenic perinatal risk factors were associated with infection in one village, while health education reduced infections in another. Among the 25 incident cases, eight were HCV-RNA negative when they were first found to be anti-HCV positive and one-third of the 15 viraemic cases with follow-up data available cleared their HCV-RNA after an average of 1.3 years. None of the 25 incident cases were jaundiced or had symptoms of hepatitis but elevated serum alanine aminotransferase levels confirmed hepatitis in nine. Our data suggest that asymptomatic HCV infections frequently occurred during the perinatal period but often cleared and that educating medical personnel on safe practices possibly reduced HCV transmission.

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.

Increase in diagnosed newly acquired hepatitis C in HIV-positive men who have sex with men across London and Brighton, 2002–2006: is this an outbreak?

Objectives:To determine the incidence of diagnosed newly acquired hepatitis C virus (HCV) in HIV-positive men who have sex with men (MSM) across London and Brighton in order to inform public...

Modelling the hepatitis C virus epidemic in Australia

Background Hepatitis C virus (HCV) infection in Australia is predominantly transmitted through injecting drug use. A reduction in the heroin supply in Australia in late 2000 and early 2001 may have impacted the number of injecting drug users (IDUs) and consequently the number of new hepatitis C infections in Australia. This paper updates estimates of HCV incidence and prevalence between 1960 and 2005. Methods Simple mathematical models were used to estimate HCV incidence among IDUs, migrants to Australia from high HCV-prevalence countries, and other HCV exposure groups. Recent trends in numbers of IDUs were based on indicators of injecting drug use. A natural history of HCV model was applied to estimate the prevalence of HCV in the population. Results The modelled best estimate of past HCV incidence showed a consistent increasing rate of HCV infections to a peak of 14,000 new seroconversions in 1999, followed by a decline in 2001–2002 coincident with the decline in heroin availability. HCV incidence was estimated to be 9700 (lower and upper limits of 6600 and 13,200) in 2005. Of these, 88.7% were estimated to be through injecting drug use, 7.2% among migrants and 4.1% through other transmission routes. An estimated 264,000 (lower and upper limits of 206,000 and 318,000) people were HCV antibody positive in 2005. Conclusions Mathematical models suggest that HCV incidence in Australia decreased from a peak of 14,000 new infections in 1999 to 9700 new infections in 2005, largely attributable to a reduction in injecting drug use. The numbers of people living with HCV in Australia is, however, estimated to continue to increase.

Reductions in hepatitis C virus and HIV infections among injecting drug users in New York City, 1990–2001

To assess trends in HIV, hepatitis C virus (HCV) and HIV/HCV infection among injecting drug users (IDU) from 1990 to 2001 in New York City. The 1990-2001 time period included a very large expansion of syringe exchange in New York City, from 250,000 to 3,000,000 syringes exchanged annually. Cross-sectional seroprevalence surveys of IDU entering drug abuse treatment in New York City, with sample sizes for HCV of 72 in 1990-1991 and 412 in 2000-2001. A structured risk behavior questionnaire was administered, and HIV and HCV testing were conducted. HCV testing was performed on de-linked stored serum samples. Over the 1990-2001 period, HIV prevalence declined from 54 to 13%. HCV prevalence declined from 80 to 59% among HIV-seronegative individuals, and from 90 to 63% overall. The estimated HCV incidence in 2000-2001 among new injectors was 18 per 100 person-years at risk. The large-scale expansion of syringe exchange was temporally associated with large reductions in both HIV and HCV prevalence. The prevalence and incidence of HCV, however, still remain at high levels among IDU in New York City.

Modelling hepatitis C virus incidence, prevalence and long-term sequelae in Australia, 2001

To plan an appropriate public health response to the hepatitis C virus (HCV) epidemic requires that estimates of HCV incidence and prevalence, and projections of the long-term sequelae of infection, are as accurate as possible. In this paper, mathematical models are used to synthesize data on the epidemiology and natural history of HCV in Australia to estimate HCV incidence and prevalence in Australia to end 2001, and project future trends in the long-term sequelae of HCV infection. Mathematical models of the HCV epidemic in Australia were developed based on estimates of the pattern of injecting drug use. Estimates of HCV infections due to injecting drug use were then adjusted to allow for HCV infections resulting from other transmission routes. Projections of the long-term sequelae of HCV infection were obtained by combining modelled HCV incidence with estimates of the progression rates to these outcomes. It was estimated that there were 210 000 (lower and upper limits of 157 000 and 252 000) people in Australia living with HCV antibodies at the end of 2001, with HCV incidence in 2001 estimated to be 16 000 (11 000-19 000). It was estimated that 6500 (5000-8000) people were living with HCV-related cirrhosis in 2001, that 175 (130-210) people developed HCV-associated liver failure, and that there were 50 (40-60) incident cases of HCV-related hepatocellular carcinoma (HCC). It was estimated that in 2001 22 500 quality adjusted life years were lost to chronic HCV infection, the majority (77%) in people with early (stage 0/1) liver disease. Model-based estimates were broadly consistent with other sources of information on the HCV epidemic in Australia. These models suggest that the prevalence of HCV-related cirrhosis and the incidence of HCV-related liver failure and HCC will more than triple in Australia by 2020.