Impact of COVID-19 pandemic on hepatocellular carcinoma surveillance in British Columbia, Canada: An interrupted time series study.

We assessed the impact of the COVID-19 pandemic on hepatocellular carcinoma (HCC) surveillance among individuals with HCV diagnosed with cirrhosis in British Columbia (BC), Canada. We used data from the British Columbia Hepatitis Testers Cohort (BC-HTC), including all individuals in the province tested for or diagnosed with HCV from 1 January 1990 to 31 December 2015, to assess HCC surveillance. To analyse the impact of the pandemic on HCC surveillance, we used pre-policy (January 2018 to February 2020) and post-policy (March to December 2020) periods. We conducted interrupted time series (ITS) analysis using a segmented linear regression model and included first-order autocorrelation terms. From January 2018 to December 2020, 6546 HCC screenings were performed among 3429 individuals with HCV and cirrhosis. The ITS model showed an immediate decrease in HCC screenings in March and April 2020, with an overall level change of -71 screenings [95% confidence interval (CI): -105.9, -18.9]. We observed a significant decrease in HCC surveillance among study participants, regardless of HCV treatment status and age group, with the sharpest decrease among untreated HCV patients. A recovery of HCC surveillance followed this decline, reflected in an increasing trend of 7.8 screenings (95% CI: 0.6, 13.5) per month during the post-policy period. There was no level or trend change in the number of individuals diagnosed with HCC. We observed a sharp decline in HCC surveillance among people living with HCV and cirrhosis in BC following the COVID-19 pandemic control measures. HCC screening returned to pre-pandemic levels by mid-2020.

Factors associated with SARS-CoV-2 infection in unvaccinated children and young adults.

BACKGROUND AND OBJECTIVES: Pediatric COVID-19 cases are often mild or asymptomatic, which has complicated estimations of disease burden using existing testing practices. We aimed to determine the age-specific population seropositivity and risk factors of SARS-CoV-2 seropositivity among children and young adults during the pandemic in British Columbia (BC). METHODS: We conducted two cross-sectional serosurveys: phase 1 enrolled children and adults < 25 years between November 2020-May 2021 and phase 2 enrolled children < 10 years between June 2021-May 2022 in BC. Participants completed electronic surveys and self-collected finger-prick dried blood spot (DBS) samples. Samples were tested for immunoglobulin G antibodies against ancestral spike protein (S). Descriptive statistics from survey data were reported and two multivariable analyses were conducted to evaluate factors associated with seropositivity. RESULTS: A total of 2864 participants were enrolled, of which 95/2167 (4.4%) participants were S-seropositive in phase 1 across all ages, and 61/697 (8.8%) unvaccinated children aged under ten years were S-seropositive in phase 2. Overall, South Asian participants had a higher seropositivity than other ethnicities (13.5% vs. 5.2%). Of 156 seropositive participants in both phases, 120 had no prior positive SARS-CoV-2 test. Young infants and young adults had the highest reported seropositivity rates (7.0% and 7.2% respectively vs. 3.0-5.6% across other age groups). CONCLUSIONS: SARS-CoV-2 seropositivity among unvaccinated children and young adults was low in May 2022, and South Asians were disproportionately infected. This work demonstrates the need for improved diagnostics and reporting strategies that account for age-specific differences in pandemic dynamics and acceptability of testing mechanisms.

"Shared experience makes this all possible": documenting the guiding principles of peer-led services for people released from prison.

BACKGROUND: There is a growing body of evidence demonstrating the effectiveness of peer-led services in supporting community reintegration for people released from prison. This study aims to document the guiding principle of a peer-led service for people released from prison, from the perspective of peer mentors. METHODS: Data were collected using focus groups (N = 10; 2 groups with 5 participants each) and one-on-one interviews (N = 5) including a total of 13 people, representing all UTGSS staff at the time of the study. An inductive thematic analysis was used to identify patterns in the data. Initial coding was done by using "in-vivo" codes (i.e. applying codes to terms used by participants). This informed the direction of the next stage of analysis, which focused on identifying categories that synthesized the codes and data across transcripts. In this stage, broad themes and sub-themes were developed. FINDINGS: Six themes were constructed to reflect the guiding principles of UTGSS staff. This includes four central themes: 1) Offering hope; 2) Building respectful relationships; 3) Providing consistent support; 4) Meeting people where they are at. Two connected themes are also reported: 1) Relying on shared experience, which participants reported serves as the foundation for practicing these guiding principles and 2) Bridging connections to services, which reflects the outcome of practicing these guiding principles. CONCLUSION: The principles identified in this study can be used by UTGSS staff as a guide for checking-in on progress with clients and may be considered as a model for reflection on practice by staff providing similar peer-led services. These principles should not be applied in a prescriptive way, as relationship building is at the centre of peer support, and different applications will be required depending on clients' goals and the range of supports available within their community.

The Impact of Current Opioid Agonist Therapy on Hepatitis C Virus Treatment Initiation Among People Who Use Drugs From the Direct-acting Antiviral (DAA) Era: A Population-Based Study.

BACKGROUND: Evidence that opioid agonist therapy (OAT) is associated with increased odds of hepatitis C virus (HCV) treatment initiation among people who use drugs (PWUD) is emerging. The objective of this study was to determine the association between current OAT and HCV treatment initiation among PWUD in a population-level linked administrative dataset. METHODS: The British Columbia Hepatitis Testers Cohort was used for this study, which includes all people tested for or diagnosed with HCV in British Columbia, linked to medical visits, hospitalizations, laboratory, prescription drug, and mortality data from 1992 until 2019. PWUD with injecting drug use or opioid use disorder and chronic HCV infection were identified for inclusion in this study. HCV treatment initiation was the main outcome, and subdistribution proportional hazards modeling was used to assess the relationship with current OAT. RESULTS: In total, 13 803 PWUD with chronic HCV were included in this study. Among those currently on OAT at the end of the study period, 47% (2704/5770) had started HCV treatment, whereas 22% (1778/8033) of those not currently on OAT had started HCV treatment. Among PWUD with chronic HCV infection, current OAT was associated with higher likelihood of HCV treatment initiation in time to event analysis (adjusted hazard ratio 1.84 [95% confidence interval {CI}, 1.50, 2.26]). CONCLUSIONS: Current OAT was associated with a higher likelihood of HCV treatment initiation. However, many PWUD with HCV currently receiving OAT have yet to receive HCV treatment. Enhanced integration between substance use care and HCV treatment is needed to improve the overall health of PWUD.

Impact of direct-acting antivirals for HCV on mortality in a large population-based cohort study.

BACKGROUND & AIMS: We evaluated the effect of direct-acting antiviral (DAA)-induced sustained virologic response (SVR) on all-cause, liver- and drug-related mortality in a population-based cohort in British Columbia, Canada. METHODS: We used data from the British Columbia Hepatitis Testers Cohort, which includes people tested for HCV since 1990, linked with data on medical visits, hospitalizations, prescription drugs and mortality. We followed people who received DAAs and people who did not receive any HCV treatment to death or December 31, 2019. We used inverse probability of treatment weighting to balance the baseline profile of treated and untreated individuals and performed multivariable proportional hazard modelling to assess the effect of DAAs on mortality. RESULTS: Our cohort comprised 10,851 people treated with DAAs (SVR 10,426 [96%], no-SVR: 425) and 10,851 matched untreated individuals. Median follow-up time was 2.2 years (IQR 1.3-3.6; maximum 6.2). The all-cause mortality rate was 19.5/1,000 person-years (PY) among the SVR group (deaths = 552), 86.5/1,000 PY among the no-SVR group (deaths = 96), and 99.2/1,000 PY among the untreated group (deaths = 2,133). In the multivariable model, SVR was associated with significant reduction in all-cause (adjusted hazard ratio [aHR] 0.19; 95% CI 0.17-0.21), liver- (adjusted subdistribution HR [asHR] 0.22, 95% CI 0.18-0.27) and drug-related mortality (asHR 0.26, 95% CI 0.21-0.32) compared to no-treatment. Older age and cirrhosis were associated with higher risk of liver-related mortality while younger age, injection drug use (IDU), problematic alcohol use and HIV/HBV co-infections were associated with a higher risk of drug-related mortality. CONCLUSIONS: DAA treatment is associated with a substantial reduction in all-cause, liver- and drug-related mortality. The association of IDU and related syndemic factors with a higher risk of drug-related mortality calls for an integrated social support, addiction, and HCV care approach among people who inject drugs. LAY SUMMARY: We assessed the effect of treatment of hepatitis C virus infection with direct-acting antiviral drugs on deaths from all causes, liver disease and drug use. We found that treatment with direct-acting antiviral drugs is associated with substantial lowering in risk of death from all causes, liver disease and drug use among people with hepatitis C virus infection.

Impact of COVID-19-related public health measures on HCV testing in British Columbia, Canada: An interrupted time series analysis.

BACKGROUND & AIMS: Public health measures introduced to limit transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), also disrupted various healthcare services in many regions worldwide, including British Columbia (BC), Canada. We assessed the impact of these measures, first introduced in BC in March 2020, on hepatitis C (HCV) testing and first-time HCV-positive diagnoses within the province. METHODS: De-identified HCV testing data for BC residents were obtained from the provincial Public Health Laboratory. Weekly changes in anti-HCV, HCV RNA and genotype testing episodes and first-time HCV-positive (anti-HCV/RNA/genotype) diagnoses from January 2018 to December 2020 were assessed and associations were determined using segmented regression models examining rates before vs after calendar week 12 of 2020, when measures were introduced. RESULTS: Average weekly HCV testing and first-time HCV-positive diagnosis rates fell immediately following the imposition of public health measures by 62.3 per 100 000 population and 2.9 episodes per 1 000 000 population, respectively (P < .0001 for both), and recovered in subsequent weeks to near pre-March 2020 levels. Average weekly anti-HCV positivity rates decreased steadily pre-restrictions and this trend remained unchanged afterwards. CONCLUSIONS: Reductions in HCV testing and first-time HCV-positive diagnosis rates, key drivers of progression along the HCV care cascade, occurred following the introduction of COVID-19-related public health measures. Further assessment will be required to better understand the full impact of these service disruptions on the HCV care cascade and to inform strategies for the re-engagement of people who may have been lost to care because of these measures.

HCV reinfection rates after cure or spontaneous clearance among HIV-infected and uninfected men who have sex with men.

BACKGROUND & AIMS: Hepatitis C virus (HCV) reinfection among high-risk groups threatens HCV elimination goals. We assessed HCV reinfection rates among men who have sex with men (MSM) in British Columbia (BC), Canada. METHODS: We used data from the BC Hepatitis Testers Cohort, which includes nearly 1.7 million individuals tested for HCV or HIV in BC. MSM who had either achieved sustained virologic response (SVR) after successful HCV treatment, or spontaneous clearance (SC) and had ≥1 subsequent HCV RNA measurement, were followed from the date of SVR or SC until the earliest of reinfection, death, or last HCV RNA measurement. Predictors of reinfection were identified by Cox proportional modelling. The earliest study start date was 6 November 1997 and latest end date was 13 April 2018. RESULTS: Of 1349 HCV-positive MSM who met the inclusion criteria, 493 had SC while 856 achieved SVR. 349 (25.65%) had HIV coinfection. We identified 98 reinfections during 5203 person-years (PYs) yielding a reinfection rate of 1.88/100PYs. The reinfection rate among SC (2.74/100PYs) was more than twice that of those with SVR (1.03/100 PYs). Problematic alcohol use (aHR 1.73, 95% CI 1.003-2.92), injection drug use (aHR 2.60, 95% CI 1.57-4.29) and HIV coinfection (aHR 2.04, 95% CI 1.29-3.23) were associated with increased risk of HCV reinfection. Mental health counselling history (aHR 0.24, 95% CI 0.13-0.46) was associated with reduced HCV reinfection risk. CONCLUSIONS: There is the need to engage MSM in harm reduction and prevention services following treatment to reduce reinfection risk.

Women in the 2019 hepatitis C cascade of care: findings from the British Columbia Hepatitis Testers cohort study.

BACKGROUND: Women living with hepatitis C virus (HCV) are rarely addressed in research and may be overrepresented within key populations requiring additional support to access HCV care and treatment. We constructed the HCV care cascade among people diagnosed with HCV in British Columbia, Canada, as of 2019 to compare progress in care and treatment and to assess sex/gender gaps in HCV treatment access. METHODS: The BC Hepatitis Testers Cohort includes 1.7 million people who tested for HCV, HIV, reported cases of hepatitis B, and active tuberculosis in BC from 2000 to 2019. Test results were linked to medical visits, hospitalizations, cancers, prescription drugs, and mortality data. Six HCV care cascade stages were identified: (1) antibody diagnosed; (2) RNA tested; (3) RNA positive; (4) genotyped; (5) initiated treatment; and (6) achieved sustained virologic response (SVR). HCV care cascade results were assessed for women, and an 'inverse' cascade was created to assess gaps, including not being RNA tested, genotyped, or treatment initiated, stratified by sex. RESULTS: In 2019, 52,638 people with known sex were anti-HCV positive in BC; 37% (19,522) were women. Confirmatory RNA tests were received by 86% (16,797/19,522) of anti-HCV positive women and 83% (27,353/33,116) of men. Among people who had been genotyped, 68% (6756/10,008) of women and 67% (12,640/18,828) of men initiated treatment, with 94% (5023/5364) of women and 92% (9147/9897) of men achieving SVR. Among the 3252 women and 6188 men not yet treated, higher proportions of women compared to men were born after 1975 (30% vs. 21%), had a mental health diagnosis (42% vs. 34%) and had used injection drugs (50% vs. 45%). Among 1619 women and 2780 men who had used injection drugs and were not yet treated, higher proportions of women than men used stimulants (64% vs. 57%), and opiates (67% vs. 60%). CONCLUSIONS: Women and men appear to be equally engaged into the HCV care cascade; however, women with concurrent social and health conditions are being left behind. Treatment access may be improved with approaches that meet the needs of younger women, those with mental health diagnoses, and women who use drugs.

Moving Towards Hepatitis C Microelimination Among People Living With Human Immunodeficiency Virus in Australia: The CEASE Study.

BACKGROUND: Microelimination of hepatitis C virus (HCV) among people living with human immunodeficiency virus (HIV) may be feasible in Australia, given unrestricted access to direct-acting antiviral (DAA) therapy from 2016. Our aim was to evaluate progress towards elimination goals within HIV/HCV-coinfected adults in Australia following universal DAA access. METHODS: The CEASE prospective cohort study enrolled adults with HIV/HCV, irrespective of viremic status, from 14 primary and tertiary clinics in Australia. Annual and cumulative HCV treatment uptake, outcome, and HCV RNA prevalence were evaluated, with follow-up through May 2018 (median follow-up, 2.63 years). Factors associated with DAA uptake were analyzed. RESULTS: Between July 2014 and March 2017, 402 participants who were HIV/HCV antibody positive were enrolled (95% male [80% gay and bisexual men,], 13% cirrhosis, 80% history of injecting drug use [39% currently injecting]). Following universal DAA access, annual HCV treatment uptake in those eligible increased from 7% and 11% per year in 2014 and 2015, respectively, to 80% in 2016. By 2018, cumulative HCV treatment uptake in those ever eligible for treatment was 91% (336/371). HCV viremic prevalence declined from 82% (95% CI, 78-86%) in 2014 to 8% (95% CI, 6-12%) in 2018. Reinfection was reported in only 5 participants for a reinfection incidence of 0.81 per 100 person-years (95% CI, 0.34-1.94). CONCLUSIONS: High uptake and effectiveness of unrestricted DAA therapy in Australia have permitted rapid treatment scale-up, with a dramatic reduction in HCV infection burden and low reinfection rate among people living with HIV, suggesting that microelimination is feasible. CLINICAL TRIALS REGISTRATION: NCT02102451.

Loss to follow-up: A significant barrier in the treatment cascade with direct-acting therapies.

Effectiveness of direct-acting antiviral (DAA) therapies could be influenced by patient characteristics such as comorbid conditions, which could lead to premature treatment discontinuation and/or irregular medical follow-ups. Here, we evaluate loss to follow-up and treatment effectiveness of sofosbuvir/ledipasvir ± ribavirin (SOF/LDV ± RBV), ombitasvir/paritaprevir/ritonavir + dasabuvir ± ribavirin (OBV/PTV/r + DSV ± RBV) for hepatitis C virus (HCV) genotype 1 (GT1) and sofosbuvir + ribavirin (SOF + RBV) for genotype 3 (GT3) in British Columbia Canada: The British Columbia Hepatitis Testers Cohort includes data on individuals tested for HCV since 1992, integrated with medical visit, hospitalization and prescription drug data. HCV-positive individuals who initiated DAA regimens, irrespective of treatment completion, for GT1 and GT3 until 31 December, 2017 were included. Factors associated with sustained virological response (SVR) and loss to follow-up were assessed by using multivariable logistic regression models. In total 4477 individuals initiated DAAs. The most common prescribed DAA was SOF/LDV ± RBV with SVR of 95%. The highest SVR of 99.5% was observed among OBV/PTV/r + DSV-treated patients. Overall, 453 (10.1%) individuals were lost to follow-up. Higher loss to follow-up was observed among GT1 patients treated with OBV (17.8%) and GT3 patients (15.7%). The loss to follow-up rate was significantly higher among individuals aged <60 years, those with a history of injection drug use (IDU), on opioid substitution therapy and with cirrhosis. Our findings indicate that loss to follow-up exceeds viral failure in HCV DAA therapy and its rate varies significantly by genotype and treatment regimen. Depending on the aetiology of lost to follow-up, personalized case management for those with medical complications and supporting services among IDU are needed to achieve the full benefits of effective treatments.

Sustained virological response from interferon-based hepatitis C regimens is associated with reduced risk of extrahepatic manifestations.

BACKGROUND & AIMS: HCV infection is associated with several extrahepatic manifestations (EHMs). We evaluated the impact of sustained virological response (SVR) on the risk of 7 EHMs that contribute to the burden of extrahepatic disease: type 2 diabetes mellitus, chronic kidney disease or end-stage renal disease, stroke, ischemic heart disease, major adverse cardiac events, mood and anxiety disorders, and rheumatoid arthritis. METHODS: A longitudinal cohort study was conducted using data from the British Columbia Hepatitis Testers Cohort, which included ~1.3 million individuals screened for HCV. We identified all HCV-infected individuals who were treated with interferon-based therapies between 1999 and 2014. SVR was defined as a negative HCV RNA test ≥24 weeks post-treatment or after end-of-treatment, if unavailable. We computed adjusted subdistribution hazard ratios (asHR) for the effect of SVR on each EHM using competing risk proportional hazard models. Subgroup analyses by birth cohort, sex, injection drug exposure and genotype were also performed. RESULTS: Overall, 10,264 HCV-infected individuals were treated with interferon, of whom 6,023 (59%) achieved SVR. Compared to those that failed treatment, EHM risk was significantly reduced among patients with SVR for type 2 diabetes mellitus (asHR 0.65; 95%CI 0.55-0.77), chronic kidney disease or end-stage renal disease (asHR 0.53; 95% CI 0.43-0.65), ischemic or hemorrhagic stroke (asHR 0.73; 95%CI 0.49-1.09), and mood and anxiety disorders (asHR 0.82; 95%CI 0.71-0.95), but not for ischemic heart disease (asHR 1.23; 95%CI 1.03-1.47), major adverse cardiac events (asHR 0.93; 95%CI 0.79-1.11) or rheumatoid arthritis (asHR 1.09; 95% CI 0.73-1.64). CONCLUSIONS: SVR was associated with a reduction in the risk of several EHMs. Increased uptake of antiviral therapy may reduce the growing burden of EHMs in this population. LAY SUMMARY: We estimated the rates of chronic comorbidities other than liver disease between those who were cured and those who failed treatment for hepatitis C virus (HCV) infection. Our findings showed that the rates of these non-liver diseases were largely reduced for those who were cured with interferon-based treatments. Early HCV treatments could provide many benefits in the prevention of various HCV complications beyond liver disease.

The population level care cascade for hepatitis C in British Columbia, Canada as of 2018: Impact of direct acting antivirals.

BACKGROUND: Population-level monitoring of hepatitis C virus (HCV) infected people across cascades of care identifies gaps in access and engagement in care and treatment. We characterized the population-level care cascade for HCV in British Columbia (BC), Canada before and after introduction of Direct Acting Antiviral (DAA) treatment. METHODS: BC Hepatitis Testers Cohort (BC-HTC) includes 1.7 million individuals tested for HCV, HIV, reported cases of hepatitis B, and active tuberculosis in BC from 1990 to 2018 linked to medical visits, hospitalizations, cancers, prescription drugs and mortality data. We defined six HCV care cascade stages: (a) antibody diagnosed; (b) RNA tested; (c) RNA positive; (d) genotyped; (e) initiated treatment; and (f) achieved sustained virologic response (SVR). RESULTS: We estimated 61 127 people were HCV antibody positive in BC in 2018 (undiagnosed: 7686, 13%; diagnosed: 53 441, 87%). Of those diagnosed, 83% (44 507) had HCV RNA testing, and of those RNA positive, 90% (28 716) were genotyped. Of those genotyped, 61% (17 441) received therapy, with 90% (15 672) reaching SVR. Individuals from older birth cohorts had lower progression to HCV RNA testing. While people who currently inject drugs had the highest proportional progression to RNA testing, this group had the lowest proportional treatment uptake. CONCLUSIONS: Although gaps in HCV RNA and genotype testing after antibody diagnosis exist, the largest gap in the care cascade is treatment initiation, despite introduction of DAA treatment and removal of treatment eligibility restrictions. Further interventions are required to ensure testing and treatment is equitably accessible in BC.

Demonstration of Near-Elimination of Hepatitis C Virus Among a Prison Population: The Lotus Glen Correctional Centre Hepatitis C Treatment Project.

Micro-elimination of hepatitis C virus (HCV) infection through rapid uptake of government-funded direct-acting antiviral therapy within an Australian prison setting is demonstrated. During a 22-month period, 119 patients initiated treatment for chronic HCV infection, with HCV in-prison viremic prevalence declining from 12% to 1%.

A molecular transmission network of recent hepatitis C infection in people with and without HIV: Implications for targeted treatment strategies.

Combining phylogenetic and network methodologies has the potential to better inform targeted interventions to prevent and treat infectious diseases. This study reconstructed a molecular transmission network for people with recent hepatitis C virus (HCV) infection and modelled the impact of targeting directly acting antiviral (DAA) treatment for HCV in the network. Participants were selected from three Australian studies of recent HCV from 2004 to 2014. HCV sequence data (Core-E2) from participants at the time of recent HCV detection were analysed to infer a network by connecting pairs of sequences whose divergence was ≤.03 substitutions/site. Logistic regression was used to identify factors associated with connectivity. Impact of targeting HCV DAAs at both HIV co-infected and random nodes was simulated (1 million replicates). Among 236 participants, 21% (n=49) were connected in the network. HCV/HIV co-infected participants (47%) were more likely to be connected compared to HCV mono-infected participants (16%) (OR 4.56; 95% CI; 2.13-9.74). Simulations targeting DAA HCV treatment to HCV/HIV co-infected individuals prevented 2.5 times more onward infections than providing DAAs to randomly selected individuals. Results demonstrate that genetic distance-based network analyses can be used to identify characteristics associated with HCV transmission, informing targeted prevention and treatment strategies.

Treatment of HCV with direct-acting antivirals on reducing mortality related to extrahepatic manifestations: a large population-based study in British Columbia, Canada.

Background: HCV infection is associated with mortality due to extrahepatic manifestations (EHM). Sustained virologic response (SVR) following direct-acting antiviral (DAA) therapy has been linked to decreased all-cause and liver-related mortality. However, evidence regarding the impact of DAA on EHM-related deaths is lacking. This study aimed to assess the impact of DAA and SVR on EHM-related mortality. Methods: The British Columbia Hepatitis Testers Cohort comprises ∼1.7 million people tested for HCV between 1990 and 2015 and is linked with administrative health data. Among individuals diagnosed with HCV by 12/31/2020, those who received at least one DAA treatment were matched to those who never received treatment by the year of their first HCV RNA positive date. We compared three groups: treated & SVR, treated & no-SVR, and untreated; and generated EHM mortality rates and incidence curves. To account for differences in baseline characteristics, we used inverse probability of treatment weights (IPTW). IPTW-weighted multivariable cause-specific Cox regression models were adjusted for competing risk and confounders. Findings: Study population included 12,815 treated (12,287 SVR, 528 no-SVR) and 12,815 untreated individuals (median follow-up 3.4 years, IQR 2.9). The untreated group had the highest EHM mortality rate (30.9 per 1000 person-years [PY], 95% CI 29.2-32.8), followed by the treated & no-SVR group (21.2 per 1000 PY, 95% CI 14.9-30.1), while the treated & SVR group had the lowest EHM mortality rate (7.9 per 1000 PY, 95% CI 7.1-8.7). In the multivariable model, EHM mortality in the treated & SVR group was significantly decreased (adjusted cause-specific hazard ratio [acsHR] 0.20, 95% CI 0.18-0.23). The treated & SVR group had significant reductions in mortality related to each of the EHMs (78-84%). Interpretation: Treatment of HCV with DAA was associated with significant reductions in EHM-related mortality. These findings emphasize the critical importance of timely diagnosis and treatment of HCV to prevent deaths associated with EHM, and have important implications for clinical practice and public health. Funding: This work was supported by the BC Centre for Disease Control and the Canadian Institutes of Health Research (CIHR) [Grant # NHC-348216, PJT-156066, and PHE-337680]. DJ has received Doctoral Research Award (#201910DF1-435705-64343) from the Canadian Institutes of Health Research (CIHR) and Doctoral fellowship from the Canadian Network on Hepatitis C (CanHepC). CanHepC is funded by a joint initiative of the Canadian Institutes of Health Research (CIHR) (NHC-142832) and the Public Health Agency of Canada (PHAC).

Impact of the COVID-19 Pandemic on Hepatitis C Treatment Initiation in British Columbia, Canada: An Interrupted Time Series Study.

We investigated the impacts of the COVID-19 pandemic on hepatitis C (HCV) treatment initiation, including by birth cohort and injection drug use status, in British Columbia (BC), Canada. Using population data from the BC COVID-19 Cohort, we conducted interrupted time series analyses, estimating changes in HCV treatment initiation following the introduction of pandemic-related policies in March 2020. The study included a pre-policy period (April 2018 to March 2020) and three follow-up periods (April to December 2020, January to December 2021, and January to December 2022). The level of HCV treatment initiation decreased by 26% in April 2020 (rate ratio 0.74, 95% confidence interval [CI] 0.60 to 0.91). Overall, no statistically significant difference in HCV treatment initiation occurred over the 2020 and 2021 post-policy periods, and an increase of 34.4% (95% CI 0.6 to 75.8) occurred in 2022 (equating to 321 additional people initiating treatment), relative to expectation. Decreases in HCV treatment initiation occurred in 2020 for people born between 1965 and 1974 (25.5%) and people who inject drugs (24.5%), relative to expectation. In summary, the pandemic was associated with short-term disruptions in HCV treatment initiation in BC, which were greater for people born 1965 to 1974 and people who inject drugs.

Association of hepatitis B virus treatment with all-cause and liver-related mortality among individuals with HBV and cirrhosis: a population-based cohort study.

Background: We evaluated the association of hepatitis B virus (HBV) treatment with all-cause, and liver-related mortality among individuals with HBV and cirrhosis in British Columbia (BC), Canada. Methods: This analysis included people diagnosed with HBV and had cirrhosis in the BC Hepatitis Testers Cohort, including data on all individuals diagnosed with HBV from 1990 to 2015 in BC and integrated with healthcare administrative data. We followed people with cirrhosis from the first cirrhosis diagnosis date until death or December 31, 2020. We compared all-cause and liver related mortality between those who received treatment and those who did not. HBV treatment was considered a time-varying variable. We performed multivariable Cox proportional hazards model and competing risk regression models to assess the association of HBV treatment with all causes, and liver-related mortality respectively using inverse probability of treatment weighted population. Findings: Among 4962 individuals with HBV and cirrhosis, 48.1% received HBV treatment. Treated individuals had a median follow-up of 2.97 years, compared to 2.87 years for untreated individuals. The treated group was older (median age 57 vs 54 years), had higher proportion of treated of males [1802 (75.50%) vs 1766 (68.8%)], from urban area [2318 (97.2%) vs 2355 (91.8%)], and from East and South Asian ethnicity [1506 (63.1%) vs 709 (27.5%)] compared to untreated group. Untreated people experienced higher all-cause mortality (115.47 vs. 35.72 per 1000 person-years) and liver-related mortality (49.86 vs. 11.39 per 1000 person-years). Multivariable models showed that HBV treatment significantly lowered the risk of all-cause mortality (adjusted hazard ratio (aHR) 0.74; 95% CI: 0.65, 0.84) and liver-related mortality (adjusted subdistribution hazard ratio (asHR) 0.72; 95% CI: 0.58, 0.89) compared to untreated individuals. Among untreated individuals with HBV, those with HCV coinfection had a higher risk of both all-cause and liver-related mortality (aHR 1.57; 95% CI: 1.22, 2.04, and asHR 1.60; 95% CI: 1.25, 2.05, respectively). Interpretation: HBV treatment was associated with a significant reduction in all-cause and liver-related mortality among individuals with cirrhosis. The findings highlight the need for treatment among individuals with HBV related cirrhosis especially those with coinfection with hepatitis C virus. Funding: This work was supported by the BC Centre for Disease Control and the Canadian Institutes of Health Research (CIHR) [Grant # NHC-142832, PJT-156066, and SC1 -178736]. JDM has received doctoral fellowship from the Canadian Network on Hepatitis C (CanHepC). DJ has received Doctoral Research Award (#201910DF1-435705-64343) from the Canadian Institutes of Health Research (CIHR) and doctoral fellowship from the CanHepC. CanHepC is funded by a joint initiative of the Canadian Institutes of Health Research (CIHR) (NHC-142832) and the Public Health Agency of Canada (PHAC).

Adaptive immune responses to two-dose COVID-19 vaccine series in healthy Canadian adults ≥ 50 years: a prospective, observational cohort study.

To evaluate immune responses to COVID-19 vaccines in adults aged 50 years and older, spike protein (S)-specific antibody concentration, avidity, and function (via angiotensin-converting enzyme 2 (ACE2) inhibition surrogate neutralization and antibody dependent cellular phagocytosis (ADCP)), as well as S-specific T cells were quantified via activation induced marker (AIM) assay in response to two-dose series. Eighty-four adults were vaccinated with either: mRNA/mRNA (mRNA-1273 and/or BNT162b2); ChAdOx1-S/mRNA; or ChAdOx1-S/ChAdOx1-S. Anti-S IgG concentrations, ADCP scores and ACE2 inhibiting antibody concentrations were highest at one-month post-second dose and declined by four-months post-second dose for all groups. mRNA/mRNA and ChAdOx1-S/mRNA schedules had significantly higher antibody responses than ChAdOx1-S/ChAdOx1-S. CD8+ T-cell responses one-month post-second dose were associated with increased ACE2 surrogate neutralization. Antibody avidity (total relative avidity index) did not change between one-month and four-months post-second dose and did not significantly differ between groups by four-months post-second dose. In determining COVID-19 correlates of protection, a measure that considers both antibody concentration and avidity should be considered.

Validation of case-ascertainment algorithms using health administrative data to identify people who inject drugs in Ontario, Canada.

OBJECTIVES: Health administrative data can be used to improve the health of people who inject drugs by informing public health surveillance and program planning, monitoring, and evaluation. However, methodological gaps in the use of these data persist due to challenges in accurately identifying injection drug use (IDU) at the population level. In this study, we validated case-ascertainment algorithms for identifying people who inject drugs using health administrative data in Ontario, Canada. STUDY DESIGN AND SETTING: Data from cohorts of people with recent (past 12 months) IDU, including those participating in community-based research studies or seeking drug treatment, were linked to health administrative data in Ontario from 1992 to 2020. We assessed the validity of algorithms to identify IDU over varying look-back periods (ie, all years of data [1992 onwards] or within the past 1-5 years), including inpatient and outpatient physician billing claims for drug use, emergency department (ED) visits or hospitalizations for drug use or injection-related infections, and opioid agonist treatment (OAT). RESULTS: Algorithms were validated using data from 15,241 people with recent IDU (918 in community cohorts and 14,323 seeking drug treatment). An algorithm consisting of ≥1 physician visit, ED visit, or hospitalization for drug use, or OAT record could effectively identify IDU history (91.6% sensitivity and 94.2% specificity) and recent IDU (using 3-year look back: 80.4% sensitivity, 99% specificity) among community cohorts. Algorithms were generally more sensitive among people who inject drugs seeking drug treatment. CONCLUSION: Validated algorithms using health administrative data performed well in identifying people who inject drugs. Despite their high sensitivity and specificity, the positive predictive value of these algorithms will vary depending on the underlying prevalence of IDU in the population in which they are applied.

Uptake of SARS-CoV-2 vaccination among structurally-marginalized people who use drugs in Vancouver, Canada.

We sought to evaluate the rates and predictors of SARS-CoV-2 vaccination among members of a structurally-marginalized population of people who use drugs (PWUD) during a targeted, community-wide, vaccination campaign in Vancouver, Canada. Interviewer-administered data were collected from study participants between June 2021 and March 2022. Generalized estimating equation analysis was used to identify factors associated with SARS-CoV-2 vaccine uptake, ascertained through a province-wide vaccine registry. Among 223 PWUD, 107 (48.0%) reported receipt of at least two SARS-CoV-2 vaccine doses at baseline and this increased to 151 (67.7%) by the end of the study period. Using social media as a source of vaccine information was negatively associated with SARS-CoV-2 vaccine uptake (Adjusted odds ratio [AOR] 0.27, 95% confidence interval [CI] 0.09-0.81) and HIV seropositivity (AOR 2.68, 95% CI 1.12-6.39) and older age (AOR 1.27, 95% CI 1.07-1.51) were positively associated with SARS-CoV-2 vaccine uptake. These findings suggest that the targeted vaccination campaign in Vancouver may be an effective model to promote SARS-CoV-2 vaccination in other jurisdictions. However, using social media as a source of vaccine information likely reduced SARS-CoV-2 vaccine uptake in PWUD arguing for further efforts to promote accessible and evidence-based vaccine information among marginalized populations.