Correction: Prevalence and risk factors for hepatitis C virus infection in an informal settlement in Karachi, Pakistan.

[This corrects the article DOI: 10.1371/journal.pgph.0002076.].

Prevalence and risk factors for hepatitis C virus infection in an informal settlement in Karachi, Pakistan.

The burden of hepatitis C virus (HCV) infection in Pakistan is amongst the highest in the world. People living in slums are likely to be at high risk of infection. Here, we describe the results of a cross-sectional survey conducted in March 2022 that aimed to quantify the prevalence of HCV infection in Machar Colony, one of the largest and oldest slum settlements in Karachi. Risk factors for HCV seropositivity were identified using multi-level logistic regression. We recruited 1,303 individuals in a random selection of 441 households from Machar Colony. The survey-adjusted HCV-seroprevalence was 13.5% (95% Confidence Interval (CI) 11.1-15.8) and survey-adjusted viraemic prevalence was 4.1% (95% CI 3.1-5.4) with a viraemic ratio of 32% (95% CI 24.3-40.5). Of 162 seropositive people, 71 (44%) reported receiving previous treatment for chronic hepatitis C. The odds of HCV seropositivity were found to increase with each additional reported therapeutic injection in the past 12 months (OR = 1.07 (95% Credible Interval (CrI) 1.00-1.13)). We found weaker evidence for a positive association between HCV seropositivity and a reported history of receiving a blood transfusion (OR = 1.72 (95% CrI 0.90-3.21)). The seroprevalence was more than double the previously reported seroprevalence in Sindh Province. The overall proportion of seropositive people that were viraemic was lower than expected. This may reflect the long-term impacts of a non-governmental clinic providing free of cost and easily accessible hepatitis C diagnosis and treatment to the population since 2015. Reuse of needles and syringes is likely to be an important driver of HCV transmission in this setting. Future public health interventions should address the expected risks associated with iatrogenic HCV transmission in this community.

DAA treatment failures in a low-resource setting with a high burden of hepatitis C infections: a case series.

Globally, 58 million people are living with hepatitis C virus (HCV) infection and 1.5 million new patients are infected every year. The advent of direct acting antivirals (DAAs) has revolutionized the treatment of HCV, opening the door to the ambitious World Health Organization HCV infection elimination strategy by 2030. However, emerging resistance to DAAs could jeopardize any hope of achieving these targets. We discuss a series of 18 patients within a resource-limited setting, who after failing standard sofosbuvir-daclatasvir-based regimen also failed to respond to advanced pan-genotypic treatment regimens, i.e. sofosbuvir-velpatasvir, sofosbuvir-velpatasvir-ribavirin and sofosbuvir-velpatasvir-voxilaprevir. To avoid the spread of refractory HCV strains within the existing epidemic, we call for increased attention and research regarding patients failing treatment on standard pan-genotypic regimens and the spread of HCV-resistant strains within the communities.

Determining the lower limit of detection required for HCV viral load assay for test of cure following direct-acting antiviral-based treatment regimens: Evidence from a global data set.

Achieving global elimination of hepatitis C virus requires a substantial scale-up of testing. Point-of-care HCV viral load assays are available as an alternative to laboratory-based assays to promote access in hard to reach or marginalized populations. The diagnostic performance and lower limit of detection are important attributes of these new assays for both diagnosis and test of cure. Therefore, our objective was to determine an acceptable LLoD for detectable HCV viraemia as a test for cure, 12 weeks post-treatment (SVR12). We assembled a global data set of patients with detectable viraemia at SVR12 from observational databases from 9 countries (Egypt, the United States, United Kingdom, Georgia, Ukraine, Myanmar, Cambodia, Pakistan, Mozambique) and two pharmaceutical-sponsored clinical trial registries. We examined the distribution of HCV viral load at SVR12 and presented the 90th, 95th, 97th and 99th percentiles. We used logistic regression to assess characteristics associated with low-level virological treatment failure (defined as <1000 IU/mL). There were 5973 cases of detectable viraemia at SVR12 from the combined data set. Median detectable HCV RNA at SVR12 was 287,986 IU/mL. The level of detection for the 95th percentile was 227 IU/mL (95% CI 170-276). Females and those with minimal fibrosis were more likely to experience low-level viraemia at SVR12 compared to men (adjusted odds ratio AOR = 1.60 95% confidence interval [CI] 1.30-1.97 and those with cirrhosis (AOR = 1.49 95% CI 1.15-1.93). In conclusion, an assay with a level of detection of 1000 IU/mL or greater may miss a proportion of those with low-level treatment failure.

Cost-effectiveness of screening and treatment using direct-acting antivirals for chronic Hepatitis C virus in a primary care setting in Karachi, Pakistan.

Despite the availability of effective direct-acting antiviral (DAA) treatments for Hepatitis C virus (HCV) infection, many people remain undiagnosed and untreated. We assessed the cost-effectiveness of a Médecins Sans Frontières (MSF) HCV screening and treatment programme within a primary health clinic in Karachi, Pakistan. A health state transition Markov model was developed to estimate the cost-effectiveness of the MSF programme. Programme cost and outcome data were analysed retrospectively. The incremental cost-effectiveness ratio (ICER) was calculated in terms of incremental cost (2016 US$) per disability-adjusted life year (DALY) averted from the provider's perspective over a lifetime horizon. The robustness of the model was evaluated using deterministic and probabilistic sensitivity analyses (PSA). The ICER for implementing testing and treatment compared to no programme was US$450/DALY averted, with 100% of PSA runs falling below the per capita Gross Domestic Product threshold for cost-effective interventions for Pakistan (US$1,422). The ICER increased to US$532/DALY averted assuming national HCV seroprevalence (5.5% versus 33% observed in the intervention). If the cost of liver disease care was included (adapted from resource use data from Cambodia which has similar GDP to Pakistan), the ICER dropped to US$148/DALY, while it became cost-saving if a recently negotiated reduced drug cost of $75/treatment course was assumed (versus $282 in base-case) in addition to cost of liver disease care. In conclusion, screening and DAA treatment for HCV infection are expected to be highly cost-effective in Pakistan, supporting the expansion of similar screening and treatment programmes across Pakistan.

Effects and cost of different strategies to eliminate hepatitis C virus transmission in Pakistan: a modelling analysis.

BACKGROUND: The WHO elimination strategy for hepatitis C virus advocates scaling up screening and treatment to reduce global hepatitis C incidence by 80% by 2030, but little is known about how this reduction could be achieved and the costs of doing so. We aimed to evaluate the effects and cost of different strategies to scale up screening and treatment of hepatitis C in Pakistan and determine what is required to meet WHO elimination targets for incidence. METHODS: We adapted a previous model of hepatitis C virus transmission, treatment, and disease progression for Pakistan, calibrating using available data to incorporate a detailed cascade of care for hepatitis C with cost data on diagnostics and hepatitis C treatment. We modelled the effect on various outcomes and costs of alternative scenarios for scaling up screening and hepatitis C treatment in 2018-30. We calibrated the model to country-level demographic data for 1960-2015 (including population growth) and to hepatitis C seroprevalence data from a national survey in 2007-08, surveys among people who inject drugs (PWID), and hepatitis C seroprevalence trends among blood donors. The cascade of care in our model begins with diagnosis of hepatitis C infection through antibody screening and RNA confirmation. Diagnosed individuals are then referred to care and started on treatment, which can result in a sustained virological response (effective cure). We report the median and 95% uncertainty interval (UI) from 1151 modelled runs. FINDINGS: One-time screening of 90% of the 2018 population by 2030, with 80% referral to treatment, was projected to lead to 13·8 million (95% UI 13·4-14·1) individuals being screened and 350 000 (315 000-385 000) treatments started annually, decreasing hepatitis C incidence by 26·5% (22·5-30·7) over 2018-30. Prioritised screening of high prevalence groups (PWID and adults aged ≥30 years) and rescreening (annually for PWID, otherwise every 10 years) are likely to increase the number screened and treated by 46·8% and decrease incidence by 50·8% (95% UI 46·1-55·0). Decreasing hepatitis C incidence by 80% is estimated to require a doubling of the primary screening rate, increasing referral to 90%, rescreening the general population every 5 years, and re-engaging those lost to follow-up every 5 years. This approach could cost US$8·1 billion, reducing to $3·9 billion with lowest costs for diagnostic tests and drugs, including health-care savings, and implementing a simplified treatment algorithm. INTERPRETATION: Pakistan will need to invest about 9·0% of its yearly health expenditure to enable sufficient scale up in screening and treatment to achieve the WHO hepatitis C elimination target of an 80% reduction in incidence by 2030. FUNDING: UNITAID.

From risk to care: the hepatitis C screening and diagnostic cascade in a primary health care clinic in Karachi, Pakistan-a cohort study.

BACKGROUND: In the high-prevalence setting of Pakistan, screening, diagnosis and treatment services for chronic hepatitis C (CHC) patients are commonly offered in specialized facilities. We aimed to describe the cascade of care in a Médecins Sans Frontières primary health care clinic offering CHC care in an informal settlement in Karachi, Pakistan. METHODS: This was a retrospective cohort analysis using routinely collected data. Three different screening algorithms were assessed among patients with one or more CHC risk factors. RESULTS: Among the 87 348 patients attending the outpatient clinic, 5003 (6%) presented with one or more risk factors. Rapid diagnostic test (RDT) positivity was 38% overall. Approximately 60% of the CHC patients across all risk categories were in the early stage of the disease, with an aspartate aminotransferase:platelet ratio index score <1. The sequential delays in the cascade differed between the three groups, with the interval between screening and treatment initiation being the shortest in the cohort tested with GeneXpert onsite. CONCLUSIONS: Delays between screening and treatment can be reduced by putting in place more patient-centric testing algorithms. New strategies, to better identify and treat the hidden at-risk populations, should be developed and implemented.