Infectious Diseases - Research Publications
Now showing items 1-12 of 265
Decentralized, Community-Based Hepatitis C Point-of-Care Testing and Direct-Acting Antiviral Treatment for People Who Inject Drugs and the General Population in Myanmar: Protocol for a Feasibility Study
(JMIR PUBLICATIONS, INC, 2020-07-01)
BACKGROUND: The advent of direct-acting antivirals (DAAs) and point-of-care (POC) testing platforms for hepatitis C allow for the decentralization of care to primary care settings. In many countries, access to DAAs is generally limited to tertiary hospitals, with limited published research documenting decentralized models of care in low-and middle-income settings. OBJECTIVE: This study aims to assess the feasibility, acceptability, effectiveness, and cost-effectiveness of decentralized community-based POC testing and DAA therapy for hepatitis C among people who inject drugs and the general population in Yangon, Myanmar. METHODS: Rapid diagnostic tests for anti-hepatitis C antibodies were carried out on-site and, if reactive, were followed by POC GeneXpert hepatitis C RNA polymerase chain reaction tests. External laboratory blood tests to exclude other major health issues were undertaken. Results were given to participants at their next appointment, with the participants commencing DAA therapy that day if a specialist review was not required. Standard clinical data were collected, and the participants completed behavioral questionnaires. The primary outcome measures are the proportion of participants receiving GeneXpert hepatitis C RNA test, the proportion of participants commencing DAA therapy, the proportion of participants completing DAA therapy, and the proportion of participants achieving sustained virological response 12 weeks after completing DAA therapy. RESULTS: Recruitment was completed on September 30, 2019. Monitoring visits and treatment outcome visits are scheduled to continue until June 2020. CONCLUSIONS: This feasibility study in Myanmar contributes to the evidence gap for community-based hepatitis C care in low- and middle-income settings. Evidence from this study will inform the scale-up of hepatitis C treatment programs in Myanmar and globally.
Clinical and Molecular Epidemiology of an Emerging Panton-Valentine Leukocidin-Positive ST5 Methicillin-Resistant Staphylococcus aureus Clone in Northern Australia
(AMER SOC MICROBIOLOGY, 2021-01-01)
Recently, we identified a Staphylococcus aureus sequence type 5 (ST5) clone in northern Australia with discrepant trimethoprim-sulfamethoxazole (SXT) susceptibility results. We aimed to identify isolates of this clone using Vitek 2 SXT resistance as a proxy and to compare its epidemiology with those of other circulating S. aureus strains. We collated Vitek 2 susceptibility data for S. aureus isolates collected through our laboratory and conducted a prospective, case-control study comparing clinical, microbiological, epidemiological, and genomic data for subsets of isolates reported as SXT resistant (cases) and SXT susceptible (controls) by Vitek 2. While overall SXT resistance rates remained relatively stable from 2011 to 2018 among 27,721 S. aureus isolates, non-multidrug-resistant methicillin-resistant S. aureus (MRSA) strains almost completely replaced multidrug-resistant MRSA strains as the predominant SXT-resistant MRSA phenotype. Demographic and clinical features of 51 case-control pairs were similar, but genotyping revealed stark differences: clonal complex 5 (CC5) MRSA predominated among SXT-resistant cases (34/51 [67%]), while CC93 MRSA predominated among susceptible controls (26/51 [51%]). All CC5 isolates were an ST5 clonal lineage that possessed the trimethoprim resistance gene dfrG within SCCmec IVo; all were SXT susceptible by Etest. The replacement of Vitek 2 reported SXT-resistant multidrug-resistant MRSA by non-multidrug-resistant MRSA appears related to the emergence of an ST5-MRSA-SCCmec IVo clone that is SXT susceptible by Etest and causes clinical disease similar to that caused by ST93-MRSA-SCCmec IVa. Reliance on Vitek 2 SXT reporting may lead to unnecessary restriction of effective oral treatment options for S. aureus infections. Whether the presence of dfrG within SCCmec IVo provides a selective advantage at the population level is currently unclear.IMPORTANCE Staphylococcus aureus is an important human pathogen that causes a wide range of clinical infections. In the past 2 decades, an epidemic of community-associated skin and soft tissue infections has been driven by S. aureus strains with specific virulence factors and resistance to beta-lactam antibiotics. Recently, an S. aureus strain with discrepant antimicrobial susceptibility testing results has emerged in northern Australia. This ST5-MRSA-SCCmec IVo clone is reported as resistant to trimethoprim-sulfamethoxazole by Vitek 2 but susceptible by phenotypic methods. ST5-MRSA-SCCmec IVo is now the second most common community-associated MRSA clone in parts of Australia and causes a spectrum of clinical disease similar to that caused by the virulent ST93-MRSA lineage. Whole-genome sequence analysis demonstrates that ST5-MRSA-SCCmecIVo is causing a clonal outbreak across a large geographical region. Although phenotypic testing suggests in vitro susceptibility to trimethoprim-sulfamethoxazole, it is unclear at this stage whether the presence of dfrG within SCCmec IVo provides a selective advantage at the population level.
Effectiveness of an Ecological Momentary Intervention for Reducing Risky Alcohol Consumption Among Young Adults: Protocol for a Three-Arm Randomized Controlled Trial
(JMIR PUBLICATIONS, INC, 2020-03-01)
BACKGROUND: Recent research has investigated the utility of mobile phone-delivered interventions for reducing risky single-occasion drinking, also known as binge drinking. In the past five years, focus has been placed on ecological momentary interventions (EMIs), which aim to deliver intervention content in correspondence to real-time assessments of behavior, also known as ecological momentary assessments (EMAs). OBJECTIVE: This study aims to assess the effect of a fully automated, tailored, mobile phone-delivered EMI termed Mobile Intervention for Drinking in Young people (MIDY) on young people's risky single-occasion drinking behavior. METHODS: We will use a three-armed randomized controlled trial design to determine the impact of MIDY on peak consumption of alcohol among young people. A list of mobile telephone numbers for random digit dialing will be generated, and researchers will telephone potential participants to screen for eligibility. Participants will be randomized into one of three intervention groups. For 6 weeks, EMI, EMA, and attention control groups will complete hourly EMA surveys on their mobile phones on Friday and Saturday nights. EMI participants will receive personalized feedback in the form of text messages corresponding to their EMA survey responses, which focus on alcohol consumption, spending, and mood. EMA participants will not receive feedback. A third group will also complete EMA and receive feedback text messages at the same time intervals, but these will be focused on sedentary behavior and technology use. All groups will also complete a short survey on Saturday and Sunday mornings, with the primary outcome measure taken on Sunday mornings. A more detailed survey will be sent on the final Sunday of the 6-week period, and then again 1 year after recruitment. RESULTS: The primary outcome measure will be an observed change (ie, reduction) in the mean peak number of drinks consumed in a single night over the 6-week intervention period between the EMI and attention control groups as measured in the weekly EMA. We expect to see a greater reduction in mean peak drinking in the EMI group compared to that in the attention control group. As a secondary aim, we will assess whether mean peak drinking is reduced in the EMA group compared to the attention control group. We will use a random-effects mixed-modeling approach using maximum-likelihood estimation to provide estimates of differences in peak drinking across time periods between those receiving the intervention (EMI) and attention control participants. An intention-to-treat approach will be taken for the analysis. Individuals and study groups will be modeled as random and fixed factors, respectively. CONCLUSIONS: This study extends our previous work investigating the efficacy of a mobile EMI (MIDY) for reducing risky drinking among young adults in Australia, and will add to the expanding literature on the use of mobile interventions for reducing risky alcohol consumption. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registration (ANZCTR): ACTRN12617001509358p; http://www.anzctr.org.au/ACTRN12617001509358p.aspx. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/14190.
A quasi-experimental text messaging trial to improve adolescent sexual and reproductive health and smoking knowledge in Indonesia
(CSIRO PUBLISHING, 2020-04-01)
Background To evaluate the feasibility and acceptability of a text message intervention to improve young people's knowledge of sexual reproductive health (SRH) and harms related to smoking in Indonesia. METHODS: A quasi-experimental short message service (SMS) trial of young people aged 16-24 years receiving twice weekly SMS over a 10-week intervention period. Pre- and post-online demographic and risk behaviour surveys were used to assess changes in knowledge. Among respondents who completed both surveys, we assessed changes in knowledge before and after SMS intervention using paired McNemar's test and differences in mean knowledge score using a paired t-test. RESULTS: In total, 555 eligible young people were enrolled into the SMS intervention; 235 (42%) completed a follow-up survey, of which 198 (84%) were matched to a baseline survey. Median age of participants was 19 years and the majority were female (63%). The mean knowledge score significantly increased between baseline and follow-up surveys for SRH questions [2.7, (95% CI 2.47, 2.94) vs 3.4 (95% CI 2.99, 3.81) (P = <0.01)] and smoking-related questions [3.8 (95% CI 3.66, 3.99) vs 4.1 (95% CI 3.99, 4.28) (P = 0.03)]. A majority of participants reported that the SMS intervention increased their knowledge (95%) and were a useful reminder (95%). CONCLUSIONS: An SMS intervention was feasible, acceptable and improved adolescents' SRH knowledge and smoking knowledge in a low- to middle-income setting. SMS interventions targeting young people need to be scaled up, with the potential to explore additional topics around healthy lifestyle, nutrition and physical activity.
Parasite-Host Dynamics throughout Antimalarial Drug Development Stages Complicate the Translation of Parasite Clearance
(AMER SOC MICROBIOLOGY, 2021-04-01)
Ensuring continued success against malaria depends on a pipeline of new antimalarials. Antimalarial drug development utilizes preclinical murine and experimental human malaria infection studies to evaluate drug efficacy. A sequential approach is typically adapted, with results from each stage informing the design of the next stage of development. The validity of this approach depends on confidence that results from murine malarial studies predict the outcome of clinical trials in humans. Parasite clearance rates following treatment are key parameters of drug efficacy. To investigate the validity of forward predictions, we developed a suite of mathematical models to capture parasite growth and drug clearance along the drug development pathway and estimated parasite clearance rates. When comparing the three infection experiments, we identified different relationships of parasite clearance with dose and different maximum parasite clearance rates. In Plasmodium berghei-NMRI mouse infections, we estimated a maximum parasite clearance rate of 0.2 (1/h); in Plasmodium falciparum-SCID mouse infections, 0.05 (1/h); and in human volunteer infection studies with P. falciparum, we found a maximum parasite clearance rate of 0.12 (1/h) and 0.18 (1/h) after treatment with OZ439 and MMV048, respectively. Sensitivity analysis revealed that host-parasite driven processes account for up to 25% of variance in parasite clearance for medium-high doses of antimalarials. Although there are limitations in translating parasite clearance rates across these experiments, they provide insight into characterizing key parameters of drug action and dose response and assist in decision-making regarding dosage for further drug development.
Multi-site assessment of rapid, point-of-care antigen testing for the diagnosis of SARS-CoV-2 infection in a low-prevalence setting: A validation and implementation study
Background: In Australia, COVID-19 diagnosis relies on RT-PCR testing which is relatively costly and time-consuming. To date, few studies have assessed the performance and implementation of rapid antigen-based SARS-CoV-2 testing in a setting with a low prevalence of COVID-19 infections, such as Australia. Methods: This study recruited participants presenting for COVID-19 testing at three Melbourne metropolitan hospitals during a period of low COVID-19 prevalence. The Abbott PanBioTM COVID-19 Ag point-of-care test was performed alongside RT-PCR. In addition, participants with COVID-19 notified to the Victorian Government were invited to provide additional swabs to aid validation. Implementation challenges were also documented. Findings: The specificity of the Abbott PanBioTM COVID-19 Ag test was 99.96% (95% CI 99.73 - 100%). Sensitivity amongst participants with RT-PCR-confirmed infection was dependent upon the duration of symptoms reported, ranging from 77.3% (duration 1 to 33 days) to 100% in those within seven days of symptom onset. A range of implementation challenges were identified which may inform future COVID-19 testing strategies in a low prevalence setting. Interpretation: Given the high specificity, antigen-based tests may be most useful in rapidly triaging public health and hospital resources while expediting confirmatory RT-PCR testing. Considering the limitations in test sensitivity and the potential for rapid transmission in susceptible populations, particularly in hospital settings, careful consideration is required for implementation of antigen testing in a low prevalence setting. Funding: This work was funded by the Victorian Department of Health and Human Services. The funder was not involved in data analysis or manuscript preparation.
HIV Antibody Fc N-Linked Glycosylation Is Associated with Viral Rebound
(CELL PRESS, 2020-12-15)
Changes in antibody glycosylation are linked to inflammation across several diseases. Alterations in bulk antibody galactosylation can predict rheumatic flares, act as a sensor for immune activation, predict gastric cancer relapse, track with biological age, shift with vaccination, change with HIV reservoir size on therapy, and decrease in HIV and HCV infections. However, whether changes in antibody Fc biology also track with reservoir rebound time remains unclear. The identification of a biomarker that could forecast viral rebound time could significantly accelerate the downselection and iterative improvement of promising HIV viral eradication strategies. Using a comprehensive antibody Fc-profiling approach, the level of HIV-specific antibody Fc N-galactosylation is significantly associated with time to rebound after treatment discontinuation across three independent cohorts. Thus virus-specific antibody glycosylation may represent a promising, simply measured marker to track reservoir reactivation.
Development of an antimicrobial stewardship implementation model involving collaboration between general practitioners and pharmacists: GPPAS study in Australian primary care
(CAMBRIDGE UNIV PRESS, 2021-01-28)
BACKGROUND: Rising antimicrobial resistance (AMR) in primary care is a growing concern and a threat to community health. The rise of AMR can be slowed down if general practitioners (GPs) and community pharmacists (CPs) could work as a team to implement antimicrobial stewardship (AMS) programs for optimal use of antimicrobial(s). However, the evidence supporting a GP pharmacist collaborative AMS implementation model (GPPAS) in primary care remains limited. AIM: With an aim to design a GPPAS model in Australia, this paper outlines how this model will be developed. METHODS: This exploratory study undertakes a systematic review, a scoping review, nationwide surveys, and qualitative interviews to design the model. Medical Research Council (MRC) framework and Normalization Process Theory are utilized as guides. Reviews will identify the list of effective GPPAS interventions. Two AMS surveys and paired interviews of GPs and CPs across Australia will explore their convergent and divergent views about the GPPAS interventions, attitudes towards collaboration in AMS and the perceived challenges of implementing GPPAS interventions. Systems Engineering Initiative for Patient Safety (SEIPS 2.0) model and factor analyses will guide the structure of GPPAS model through identifying the determinants of GPPAS uptake. The implementable GPPAS strategies will be selected based on empirical feasibility assessment by AMS stakeholders using the APEASE (Affordability, Practicability, Effectiveness and cost-effectiveness, Acceptability, Side-effects and safety, Equity) criteria. DISCUSSION: The GPPAS model might have potential implications to inform how to better involve GPs and CPs in AMS, and, to improve collaborative services to optimize antimicrobial use and reduce AMR in primary care.
Self-clearance of Mycobacterium tuberculosis infection: implications for lifetime risk and population at-risk of tuberculosis disease
(ROYAL SOC, 2021-01-27)
Background: it is widely assumed that individuals with Mycobacterium tuberculosis (Mtb) infection remain at lifelong risk of tuberculosis (TB) disease. However, there is substantial evidence that self-clearance of Mtb infection can occur. We infer a curve of self-clearance by time since infection and explore its implications for TB epidemiology. Methods and findings: data for self-clearance were inferred using post-mortem and tuberculin-skin-test reversion studies. A cohort model allowing for self-clearance was fitted in a Bayesian framework before estimating the lifetime risk of TB disease and the population infected with Mtb in India, China and Japan in 2019. We estimated that 24.4% (17.8-32.6%, 95% uncertainty interval (UI)) of individuals self-clear within 10 years of infection, and 73.1% (64.6-81.7%) over a lifetime. The lifetime risk of TB disease was 17.0% (10.9-22.5%), compared to 12.6% (10.1-15.0%) assuming lifelong infection. The population at risk of TB disease in India, China and Japan was 35-80% (95% UI) smaller in the self-clearance scenario. Conclusions: the population with a viable Mtb infection may be markedly smaller than generally assumed, with such individuals at greater risk of TB disease. The ability to identify these individuals could dramatically improve the targeting of preventive programmes and inform TB vaccine development, bringing TB elimination within reach of feasibility.
Global hepatitis C elimination: an investment framework
(ELSEVIER INC, 2020-10-01)
WHO has set global targets for the elimination of hepatitis B and hepatitis C as a public health threat by 2030. However, investment in elimination programmes remains low. To help drive political commitment and catalyse domestic and international financing, we have developed a global investment framework for the elimination of hepatitis B and hepatitis C. The global investment framework presented in this Health Policy paper outlines national and international activities that will enable reductions in hepatitis C incidence and mortality, and identifies potential sources of funding and tools to help countries build the economic case for investing in national elimination activities. The goal of this framework is to provide a way for countries, particularly those with minimal resources, to gain the substantial economic benefit and cost savings that come from investing in hepatitis C elimination.
Five insights from the Global Burden of Disease Study 2019
(ELSEVIER SCIENCE INC, 2020-10-17)
The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a rules-based synthesis of the available evidence on levels and trends in health outcomes, a diverse set of risk factors, and health system responses. GBD 2019 covered 204 countries and territories, as well as first administrative level disaggregations for 22 countries, from 1990 to 2019. Because GBD is highly standardised and comprehensive, spanning both fatal and non-fatal outcomes, and uses a mutually exclusive and collectively exhaustive list of hierarchical disease and injury causes, the study provides a powerful basis for detailed and broad insights on global health trends and emerging challenges. GBD 2019 incorporates data from 281 586 sources and provides more than 3·5 billion estimates of health outcome and health system measures of interest for global, national, and subnational policy dialogue. All GBD estimates are publicly available and adhere to the Guidelines on Accurate and Transparent Health Estimate Reporting. From this vast amount of information, five key insights that are important for health, social, and economic development strategies have been distilled. These insights are subject to the many limitations outlined in each of the component GBD capstone papers.
The Use of Test-negative Controls to Monitor Vaccine Effectiveness A Systematic Review of Methodology
(LIPPINCOTT WILLIAMS & WILKINS, 2020-01-01)
BACKGROUND: The test-negative design is an increasingly popular approach for estimating vaccine effectiveness (VE) due to its efficiency. This review aims to examine published test-negative design studies of VE and to explore similarities and differences in methodological choices for different diseases and vaccines. METHODS: We conducted a systematic search on PubMed, Web of Science, and Medline, for studies reporting the effectiveness of any vaccines using a test-negative design. We screened titles and abstracts and reviewed full texts to identify relevant articles. We created a standardized form for each included article to extract information on the pathogen of interest, vaccine(s) being evaluated, study setting, clinical case definition, choices of cases and controls, and statistical approaches used to estimate VE. RESULTS: We identified a total of 348 articles, including studies on VE against influenza virus (n = 253), rotavirus (n = 48), pneumococcus (n = 24), and nine other pathogens. Clinical case definitions used to enroll patients were similar by pathogens of interest but the sets of symptoms that defined them varied substantially. Controls could be those testing negative for the pathogen of interest, those testing positive for nonvaccine type of the pathogen of interest, or a subset of those testing positive for alternative pathogens. Most studies controlled for age, calendar time, and comorbidities. CONCLUSIONS: Our review highlights similarities and differences in the application of the test-negative design that deserve further examination. If vaccination reduces disease severity in breakthrough infections, particular care must be taken in interpreting vaccine effectiveness estimates from test-negative design studies.