Brendan P Jacka

Brendan P Jacka
Brown University · Department of Epidemiology

BSc, MSc, PhD

About

62
Publications
5,638
Reads
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519
Citations
Introduction
I conduct research in epidemiology (public health, clinical, and laboratory), infectious disease (hepatitis C virus and HIV), and substance use (people who inject drugs and men who use image and performance enhancing drugs). My research methods include survival analysis of people at risk of hepatitis C virus infection, phylogenetic analysis to understand transmission dynamics, and indirect estimates of hidden populations. I apply novel analytic methodologies (such as Bayesian phylodynamics and latent class analysis) to better understand the complexities of both infection and addiction. My current research investigates the individual, social and structural determinants of health in minority populations.
Additional affiliations
January 2020 - present
Brown University
Position
  • Investigator
June 2019 - December 2019
Brown University
Position
  • PostDoc Position
July 2017 - June 2019
Centre de recherche du CHUM
Position
  • PostDoc Position
Education
July 2011 - December 2015
UNSW Sydney
Field of study
  • Epidemiology
February 2009 - June 2011
UNSW Sydney
Field of study
  • Pathology
February 2001 - June 2006
UNSW Sydney
Field of study
  • Biotechnology

Publications

Publications (62)
Article
Study Objective ED-based naloxone distribution and peer-based behavioral counseling have been shown to be feasible, but little is known about utilization maintenance over time and clinician, patient, and visit level factors influencing implementation. Methods We conducted a retrospective cohort study of an ED overdose prevention program providing...
Article
Full-text available
Study Objective: The opioid epidemic in the United States remains a pressing public health concern. For many individuals with opioid use disorder (OUD), the emergency department (ED) may be their only contact point with the healthcare system. Opioid-related ED visits may be a critical time for interventions to prevent negative health consequences (...
Article
Background Emergency department (ED) visits for opioid-related overdoses continue to rise across the United States, particularly among Black, Latinx, and American Indian/Alaskan Native communities. A minority of people with opioid use disorder (OUD) engages in formal addiction treatment and racial disparities in treatment access exist. ED visits fo...
Article
Introduction An ED visit for opioid overdose may be a person's only contact with the medical and behavioral health care systems and is an important opportunity to reduce risk of subsequent overdose and death. While ED initiatives to engage people with opioid use disorder (OUD) are being increasingly implemented, there are significant gaps in the re...
Article
Full-text available
As HIV incidence among people who inject drugs grows in the context of an escalating drug overdose epidemic in North America, investigating how network structure may affect vulnerability to rapid HIV transmission is necessary for preventing outbreaks. We compared the characteristics of the observed contact tracing network from the 2015 outbreak in...
Article
Background The COVID-19 pandemic significantly altered treatment delivery for opioid treatment programs (OTPs) dispensing medications for opioid use disorder (MOUD). We aimed to identify patterns of substance use among MOUD patients and examine whether COVID-19-related impacts on access to healthcare varied across subgroups. Methods This analysis...
Article
Full-text available
Background Opioid overdose deaths involving synthetic opioids, particularly illicitly manufactured fentanyl, remain a substantial public health concern in North America. Responses to overdose events (e.g., administration of naloxone and rescue breathing) are effective at reducing mortality; however, more interventions are needed to prevent overdose...
Article
Purpose: Drug overdose mortality remains a public health concern in many countries globally. In the US, overdoses involving synthetic opioids are the primary contributor to overdose mortality. We aimed to assess trends in overdose death due to synthetic opioids among young people and describe key demographic and temporal changes. Methods: Data fro...
Article
Full-text available
Recent studies have highlighted the efficacy of and willingness to use pre-exposure prophylaxis (PrEP) to prevent HIV infection among people who inject drugs (PWID), however knowledge of real-world applicability is limited. We aimed to quantify the real-world eligibility for HIV-PrEP among HIV-negative PWID in Montreal, Canada (n = 718). Eligibilit...
Preprint
Full-text available
Background: Opioid overdose deaths involving synthetic opioids, particularly illicitly manufactured fentanyl, remain a substantial public health concern in North America. Responses to overdose events (e.g. administration of naloxone and rescue breathing) are effective at reducing mortality; however, more interventions are needed to prevent overdose...
Article
Background & aims Disbursement of income assistance has been temporally associated with intensified drug use and related harms (coined the ‘cheque effect’). However, relationships to injection drug use (IDU) remain understudied. We examined short‐term ‘cheque effects’ and associated factors among people who inject drugs (PWID). Design Cross‐sectio...
Article
Objectives. To determine the number of people who inject drugs (PWID) in Canada and the annual coverage of opioid agonist treatment (OAT) and needle-and-syringe provision for PWID. Methods. We estimated the number of PWID in 11 of 13 Canadian provinces and territories in 2011 by using indirect multiplier methods based on provincial and territorial...
Article
Background: Although people who inject performance- and image-enhancing drugs (PIEDs) report fewer unsafe injecting practices, stigma and discrimination may negatively impact their access to help and information. Engagement with health care services, compared with social networks (friends, relatives, and gym associates) and the Internet and media (...
Article
The global scale‐up of hepatitis C virus (HCV) diagnosis requires simplified and affordable HCV diagnostic pathways. This study evaluated the sensitivity and specificity of the HCV Architect core antigen (HCVcAg) assay for detection of active HCV infection in plasma and capillary whole‐blood dried blood spots (DBS) compared to HCV RNA testing in pl...
Article
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...
Article
Full-text available
Background: Opioid agonist treatment is considered important in preventing acquisition of hepatitis C virus (HCV) among people who inject drugs; however, the role of dosage in opioid agonist treatment is unclear. We investigated the joint association of prescribed dosage of opioid agonist treatment and patient-perceived dosage adequacy with risk o...
Article
As direct-acting antiviral (DAA) therapy costs fall and eligibility criteria are relaxed, people who inject drugs (PWID) will increasingly become eligible for HCV treatment. Yet eligibility does not necessarily equate to access. Amidst efforts to expand treatment uptake in this population, we seek to synthesise and clarify the conceptual underpinni...
Article
Background: Multiple barriers for accessing hepatitis C virus (HCV) treatment were identified during the interferon-based (IFN) treatment era for people who inject drugs (PWID). Whether these barriers persist since the introduction of IFN-free direct-acting antiviral (DAA) agents in Canada remains to be documented. This study examined temporal tre...
Article
Full-text available
Introduction and Aims Needle‐syringe programs (NSP) are an underutilized source of data on drug injection trends; these data are essential for informing public health interventions. We examine trends in NSP service occasions from 2007–2015. Design and Methods Using standardised data from 26 NSP outlets through the Queensland NSP Minimum Data Set (...
Data
Data S1. Supplementary Materials and Methods. Figure S1. Maximum likelihood phylogenetic trees inferred from available hepatitis C virus (HCV) Core‐E2 sequence from five studies of recent HCV infection in Australia and New Zealand recruited between 2004 and 2015. Table S1. Multivariate logistic regression of factors associated with phylogenetic c...
Article
Full-text available
Introduction Over the last two decades, the incidence of hepatitis C virus (HCV) co‐infection among men who have sex with men (MSM) living with HIV began increasing in post‐industrialized countries. Little is known about transmission of acute or recent HCV, in particular among MSM living with HIV co‐infection, which creates uncertainty about potent...
Article
Introduction and aims: Emerging research suggests that the sub-population of anabolic-androgenic steroid (AAS) users who experience physical appearance concerns may suffer greater psychological dysfunction than other sub-populations, including users with athletic or occupational concerns. Thus, among current AAS users, we sought to determine wheth...
Article
Background: Increased utilisation of needle-syringe programs (NSP) by men who inject performance and image-enhancing drugs (PIEDs) has been reported. While fewer in number, people who inject PIEDs possess distinct service and knowledge needs compared to other NSP clients. Methods: Using standardised data from 26 NSP outlets through the Queenslan...
Article
Full-text available
Background: This study estimated latent classes (i.e., unobserved subgroups in a population) of people who use drugs in Vancouver, Canada and examined how these classes relate to phylogenetic clustering of hepatitis C virus (HCV) infection. Methods: HCV antibody positive people who use drugs from two cohorts in Vancouver, Canada (1996-2012) with...
Article
Full-text available
The significance of the clinical impact of direct-acting antiviral (DAA) resistance-associated substitutions (RASs) in hepatitis C virus (HCV) on treatment failure is unclear. No standardized methods or guidelines for detection of DAA RASs in HCV exist. To facilitate further evaluations of the impact of DAA RASs in HCV, we conducted a systematic re...
Article
Full-text available
Background: This study aimed to investigate the potential influence of venue-based networks on HCV transmission in HIV-positive gay and bisexual men (GBM). Methods: This was a prospectively recruited cohort of HIV-infected GBM with recently-acquired HCV infection resident in Melbourne and Sydney. Clinical and demographic data were collected toge...
Data
Histories of injection drug use and sexual behaviour for ten men with discordance between clinician and participant-assigned mode of HCV acquisition. (PDF)
Data
Association between 1-mode social networks and phylogenetic clustering according to different genetic distance thresholds. (PDF)
Data
Study questionnaire instrument. (PDF)
Data
Study interview schedule. (PDF)
Data
Generation of NS5B amplicons. (PDF)
Data
Potential mechanisms for entry into study through (A) clinical hepatitis definition or (B) antibody seroconversion definition. (PDF)
Article
Effective surveillance and treatment strategies are required to control the hepatitis C virus (HCV) epidemic. Phylogenetic analyses are powerful tools for reconstructing the evolutionary history of viral outbreaks and identifying transmission clusters. These studies often rely on Sanger sequencing which typically generates a single consensus sequen...
Article
Full-text available
Background & aims: Understanding HCV transmission among people who inject drugs (PWID) is important for designing prevention strategies. This study investigated whether HCV infection among younger injectors occurs from few or many transmission events from older injectors to younger injectors among PWID in Vancouver, Canada. Methods: HCV antibody...
Article
The aim of this study was to identify factors associated with phylogenetic clustering among people with recently acquired hepatitis C virus (HCV) infection. Participants with available sample at time of HCV detection were selected from three studies; the Australian Trial in Acute Hepatitis C, the Hepatitis C Incidence and Transmission Study - Priso...
Article
Full-text available
Sequencing is important for understanding the molecular epidemiology and viral evolution of hepatitis C virus (HCV) infection. To date, there is little standardisation among sequencing protocols, in-part due to the high genetic diversity that is observed within HCV. This study aimed to develop a novel, practical sequencing protocol that covered bot...
Article
Full-text available
Many people living with hepatitis C virus (HCV) infection will continue to rely on interferon-based regimens until effective strategies to minimize the cost of directly acting antivirals (DAAs) and to improve treatment access are implemented. Host single-nucleotide polymorphisms related to IFNL3 and IFNL4 are associated with spontaneous clearance o...
Article
Full-text available
Improved surveillance methods are needed to better understand the current Hepatitis C virus (HCV) disease burden and to monitor the impact of prevention and treatment interventions on HCV transmission dynamics. Sanger sequencing (HCV NS5B, HVR1 and Core-E1-HVR1) and phylogenetics were applied to samples from individuals diagnosed with HCV in Britis...
Article
Full-text available
Unlabelled: Little is known about factors associated with hepatitis C virus (HCV) transmission among people who inject drugs (PWID). Phylogenetic clustering and associated factors were evaluated among PWID in Vancouver, Canada. Data were derived from the Vancouver Injection Drug Users Study. Participants who were HCV antibody-positive at enrolment...
Data
Database of HCV sequencing amplicons. Including author list, title, date of publication, and journal of accepted publications, selected primer sequence (where available) and 5′- and 3′-location of primers. (XLSX)
Data
Distribution of sequencing amplicons according to size and year of publication. The size distribution of HCV amplicons (A) shows a bias towards products smaller than 1000 bp in length, with fewer than 10% of amplicons being larger than this. There is a rapid increase in the number of publications until a peak in 1996. The decrease in reported seque...
Article
Full-text available
Since the identification of hepatitis C virus (HCV), viral sequencing has been important in understanding HCV classification, epidemiology, evolution, transmission clustering, treatment response and natural history. The length and diversity of the HCV genome has resulted in analysis of certain regions of the virus, however there has been little sta...
Article
Full-text available
The storage of biological samples may affect detection of viral nucleic acid, yet the stability of viral nucleic acid at standard laboratory storage temperatures (-70°C and -20°C) has not been comprehensively assessed. Deterioration of viral RNA and DNA during storage may affect the detection of viruses, thus leading to an increased likelihood of f...
Article
Full-text available
Serology assays for standard screening are optimised for use with sera collected from living adults and children. Because of potential changes in the vascular compartments after death, methods used for screening sera from cadaveric organ donors need to be validated before testing these specimens. Serum was separated from blood collected from cadave...
Article
Full-text available
Needlestick injuries are an occupational hazard for prison officers. This study aimed to assess the presence of hepatitis C virus (HCV) in syringes found in prisons. Sixty-nine syringes found in prisons were tested for HCV RNA using previously published methods. Three syringes tested positive for HCV RNA. Compared to the prevalence of HCV among inj...

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Projects

Projects (4)
Project
Hepatitis C virus (HCV) elimination targets set forth by the World Health Organisation include reductions in both acquisition of new infections and in the morbidity and mortality associated with active HCV infection. This project aimed to understand the individual and contextual factors associated with HCV infection, as well as uptake and outcomes of HCV treatment in a highly vulnerable population.
Project
Project Main Description: This project aims to describe patterns of AAS and PIEDs use; where people are sourcing them from and why; users' experience of harms; and users' utilisation of health services. Rationale: There are indicators that the small group who use PIEDs may be growing. There have been recent increases in number of Australian Needle and Syringe Program Survey (ANSPS) respondents reporting PIEDs as last drug injected. There have also been recent increases in detections of PIEDs at the Australian border – detections are now at the highest levels reported in the last decade. In addition, national steroid seizures and arrests have also increased and are the highest on record.
Project
Viral genomic analysis of hepatitis C virus in people acutely and chronically infected, undertaken in projects associated with Kirby Institute's Viral Hepatitis Clinical Research Program (VHCRP).