Vaccination coverage among people who inject drugs: A systematic review.

BACKGROUND: People who inject drugs may be at excess risk of acquiring vaccine-preventable diseases and negative associated health outcomes, but experience barriers to vaccination. We aimed to determine vaccination coverage among people who inject drugs globally. METHODOLOGY: We conducted systematic searches of the peer-reviewed and grey literature, date limited from January 2008 to August 2023, focusing on diseases for which people who inject drugs are at elevated risk for and for which an adult vaccination dose is recommended (COVID-19, hepatitis A, hepatitis B, human papillomavirus, influenza, pneumococcal disease, tetanus). To summarise available data, we conducted a narrative synthesis. RESULTS: We included 78 studies/reports comprising 117 estimates of vaccination coverage across 36 countries. Most estimates were obtained from high income countries (80%, n=94). We located estimates for hepatitis B vaccination in 33 countries, which included 18 countries with data on serological evidence of vaccine-derived hepatitis B immunity (range: 6-53%) and 22 countries with self-report data for vaccine uptake (<1-96%). Data for other vaccines were scarcer: reported hepatitis A vaccination coverage ranged 3-89% (five countries), COVID-19 ranged 4-84% (five countries), while we located estimates from fewer than five countries for influenza, tetanus, pneumococcal disease, and human papillomavirus. CONCLUSION: Estimates were sparse but where available indicative of suboptimal vaccination coverage among people who inject drugs. Improving the consistency, timeliness, and geographic coverage of vaccine uptake data among this population is essential to inform efforts to increase uptake.

The cascade of care for hepatitis C in Victoria, Australia: a data linkage cohort study.

BACKGROUND: Highly effective hepatitis C therapies are available in Australia. However, people living with hepatitis C face various barriers to accessing care and treatment. AIMS: To identify gaps in the cascade of care for hepatitis C and generate estimates of the number living with untreated infection according to population group, using a representative longitudinal study population. METHODS: We linked hepatitis C notification data from Victoria to national pathology, prescribing and death registry data. We assessed receipt of key clinical services in a large cohort who tested positive for hepatitis C from 1 January 2000 to 31 December 2016, with follow-up to 30 June 2018. We estimated the number still living with hepatitis C, adjusting for spontaneous clearance and mortality. RESULTS: The cohort comprised 45 391 people positive for hepatitis C. Of these, 13 346 (29%) received treatment and an estimated 28% (95% confidence interval (CI): 26-30%) were still living with chronic infection at 30 June 2018, with the remainder still living following spontaneous clearance (30%, 95% CI: 29-32%) or having died (12%, 95% CI: 12-12%). Half (50%) of those still living with hepatitis C were born from 1965 to 1980, and 74% first tested positive before 2011. CONCLUSIONS: Despite an enabling policy environment and subsidised therapy, many people in this cohort were not treated. Increased measures may be needed to engage people in care, including those who acquired hepatitis C more than 10 years ago.

Effectiveness of community-based oral antiviral treatments against severe COVID-19 outcomes in people 70 years and over in Victoria, Australia, 2022: an observational study.

Background: Oral Antiviral (OAV) COVID-19 treatments are widely used, but evidence for their effectiveness against the Omicron variant in higher risk, vaccinated individuals is limited. Methods: Retrospective study of two vaccinated cohorts of COVID-19 cases aged ≥70 years diagnosed during a BA.4/5 Omicron wave in Victoria, Australia. Cases received either nirmatrelvir-ritonavir or molnupiravir as their only treatment. Data linkage and logistic regression modelling was used to evaluate the association between treatment and death and hospitalisation and compared with no treatment. Findings: Of 38,933 individuals in the mortality study population, 13.5% (n = 5250) received nirmatrelvir-ritonavir, 51.3% (n = 19,962) received molnupiravir and 35.2% (n = 13,721) were untreated. Treatment was associated with a 57% (OR = 0.43, 95% CI 0.36-0.51) reduction in the odds of death, 73% (OR = 0.27, 95% CI 0.17-0.40) for nirmatrelvir-ritonavir and 55% (OR = 0.45, 95% CI 0.38-0.54) for molnupiravir. Treatment was associated with a 31% (OR = 0.69, 95% CI 0.55-0.86) reduction in the odds of hospitalisation, 40% (OR = 0.60, 95% CI 0.43-0.83) for nirmatrelvir-ritonavir and 29% (OR = 0.71, 95% CI 0.58-0.87) for molnupiravir. Cases treated within 1 day of diagnosis had a 61% reduction in the odds of death (OR = 0.39, 95% CI 0.33-0.46) compared with 33% reduction for a delay of 4 or more days (OR = 0.67, 95% CI 0.44-0.97). Interpretation: Treatment with both nirmatrelvir-ritonavir or molnupiravir was associated with a reduction in death and hospitalisation in vaccinated ≥70 years individuals during the Omicron era. Timely, equitable treatment with OAVs is an important tool in the fight against COVID-19. Funding: There was no funding for this study.

Excess mortality among people with communicable diseases over a 30-year period, Victoria, Australia: a whole of population cohort study.

Background: Understanding mortality burden associated with communicable diseases is key to informing resource allocation, disease prevention and control efforts, and evaluating public health interventions. We quantified excess mortality among people notified with communicable diseases in Victoria, Australia. Methods: Cases of communicable disease notified in Victoria between 1 January 1991 and 31 December 2021 were linked to the death registry. Informational gain obtained through linkage and 30-day case fatality rates were calculated for each disease. Standardised mortality ratios (SMR) and 95% confidence intervals were calculated up to a year following illness onset. Findings: There were 1,032,619 cases and 5985 (0.58%) died ≤30 days of illness onset. Following linkage, the 30-day case fatality rate increased more than 2-fold. Diseases with high 7-day SMR signifying excess mortality included invasive pneumococcal disease (167.7, 95% CI 153.4-182.7); listeriosis (166.2, 95% CI 121.2-218.3); invasive meningococcal disease (145.9, 95% CI 116.7-178.3); legionellosis (43.3, 95% CI 28.0-62.0); and COVID-19 (21.9, 95% CI 19.7-24.3). Most diseases exhibited a strong negative gradient, with high SMRs in the first 7-days of illness onset that reduced over time. Interpretation: We demonstrated that the rate of death in Victoria's notifiable disease surveillance dataset is underestimated. Further, compared to a general population, there is evidence of elevated all-cause mortality among people notified with communicable diseases often up to one year following illness onset. Not all elevated risk is likely directly attributable to the communicable diseases of interest, rather, it may reflect underlying comorbidities or behaviours in these individuals. Regardless of attribution, infection with communicable diseases may represent a marker of mortality. Key to preventing deaths may be through timely and appropriate transition to primary and preventive healthcare following diagnosis. Funding: No funding was provided for this study.

Missed opportunities for diagnosis of hepatitis B and C in individuals diagnosed with decompensated cirrhosis or hepatocellular carcinoma.

BACKGROUND AND AIM: This study aimed to assess utilization of health-care services in people with decompensated cirrhosis (DC) or hepatocellular carcinoma (HCC) and a "late diagnosis" of hepatitis B or hepatitis C. METHODS: Hepatitis B and C cases during 1997-2016 in Victoria, Australia, were linked with hospitalizations, deaths, liver cancer diagnoses, and medical services. A late diagnosis was defined as hepatitis B or hepatitis C notification occurring after, at the same time, or within 2 years preceding an HCC/DC diagnosis. Services provided during the 10-year period before HCC/DC diagnosis were assessed, including general practitioner (GP) or specialist visits, emergency department presentations, hospital admissions, and blood tests. RESULTS: Of the 25 766 notified cases of hepatitis B, 751 (2.9%) were diagnosed with HCC/DC, and hepatitis B was diagnosed late in 385 (51.3%). Of 44 317 cases of hepatitis C, 2576 (5.8%) were diagnosed with HCC/DC, and hepatitis C was diagnosed late in 857 (33.3%). Although late diagnosis dropped over time, missed opportunities for timely diagnosis were observed. Most people diagnosed late had visited a GP (97.4% for hepatitis B, 98.9% for hepatitis C) or had a blood test (90.9% for hepatitis B, 88.6% for hepatitis C) during the 10 years before HCC/DC diagnosis. The median number of GP visits was 24 and 32, and blood tests 7 and 8, for hepatitis B and C, respectively. CONCLUSIONS: Late diagnosis of viral hepatitis remains a concern, with the majority having frequent health-care service provision in the preceding period, indicating missed opportunities for diagnosis.

Modelling jurisdictional disparities in the cascade of care for chronic hepatitis B in Australia: impact of treatment uptake on mortality.

OBJECTIVE: Investigate the cascade of care for chronic hepatitis B (CHB) and estimate impacts of increasing treatment uptake on attributable burden, according to jurisdiction. METHODS: A mathematical model of CHB in Australia was utilised, combined with notifiable disease and Medicare data. We estimated the proportion with CHB who were diagnosed, engaged in care and receiving treatment in each state/territory, and projected future mortality. RESULTS: The highest uptake of all measures was in New South Wales, however, the largest increase over time occurred in Northern Territory. No jurisdiction is due to meet 2022 targets of treatment uptake or mortality reduction. Previously declining mortality is predicted to plateau or increase in all jurisdictions except Northern Territory. The largest gap in the cascade of care was most commonly diagnosed individuals not engaged in care; however, in Victoria and Tasmania it was lack of diagnosis. CONCLUSIONS: Measures of the cascade of care varied substantially between jurisdictions; while all require improvements to reduce mortality, the specific gaps vary, as do potential impacts. IMPLICATIONS FOR PUBLIC HEALTH: Improving the cascade of care for CHB will require jurisdictionally tailored approaches. If improvements are not made, more deaths will occur due to CHB in most states and territories.

Associations between COVID-19 and hospitalisation with respiratory and non-respiratory conditions: a record linkage study.

OBJECTIVES: To assess associations between SARS-CoV-2 infection and the incidence of hospitalisation with selected respiratory and non-respiratory conditions in a largely SARS-CoV-2 vaccine-naïve population . DESIGN, SETTING, PARTICIPANTS: Self-control case series; analysis of population-wide surveillance and administrative data for all laboratory-confirmed COVID-19 cases notified to the Victorian Department of Health (onset, 23 January 2020 - 31 May 2021; ie, prior to widespread vaccination rollout) and linked hospital admissions data (admission dates to 30 September 2021). MAIN OUTCOME MEASURES: Hospitalisation of people with acute COVID-19; incidence rate ratios (IRRs) comparing incidence of hospitalisations with defined conditions (including cardiac, cerebrovascular, venous thrombo-embolic, coagulative, and renal disorders) from three days before to within 89 days of onset of COVID-19 with incidence during baseline period (60-365 days prior to COVID-19 onset). RESULTS: A total of 20 594 COVID-19 cases were notified; 2992 people (14.5%) were hospitalised with COVID-19. The incidence of hospitalisation within 89 days of onset of COVID-19 was higher than during the baseline period for several conditions, including myocarditis and pericarditis (IRR, 14.8; 95% CI, 3.2-68.3), thrombocytopenia (IRR, 7.4; 95% CI, 4.4-12.5), pulmonary embolism (IRR, 6.4; 95% CI, 3.6-11.4), acute myocardial infarction (IRR, 3.9; 95% CI, 2.6-5.8), and cerebral infarction (IRR, 2.3; 95% CI, 1.4-3.9). CONCLUSION: SARS-CoV-2 infection is associated with higher incidence of hospitalisation with several respiratory and non-respiratory conditions. Our findings reinforce the value of COVID-19 mitigation measures such as vaccination, and awareness of these associations should assist the clinical management of people with histories of SARS-CoV-2 infection.

Australian consensus recommendations for the management of hepatitis B.

INTRODUCTION: The prevalence of hepatitis B virus (HBV) infection in Australia is nearly 1%. In certain well defined groups the prevalence is far greater, yet an estimated 27% of people living with HBV infection remain undiagnosed. Appropriate screening improves detection, increases opportunity for treatment, and ultimately reduces the significant morbidity and mortality associated with the development of liver fibrosis and hepatocellular carcinoma (HCC). MAIN RECOMMENDATIONS: This statement highlights important aspects of HBV infection management in Australia. There have been recent changes in nomenclature and understanding of natural history, as well as a newly defined upper limit of normal for liver tests that determine phase classification and threshold for antiviral treatment. As the main burden of hepatitis B in Australia is within migrant and Indigenous communities, early identification and management of people living with hepatitis B is essential to prevent adverse outcomes including liver cancer and cirrhosis. CHANGE IN MANAGEMENT AS A RESULT OF THIS GUIDELINE: These recommendations aim to raise awareness of the current management of hepatitis B in Australia. Critically, the timely identification of individuals living with hepatitis B, and where appropriate, commencement of antiviral therapy, can prevent the development of cirrhosis, HCC and mother-to-child transmission as well as hepatitis B reactivation in immunocompromised individuals. Recognising patient and viral factors that predispose to the development of cirrhosis and HCC will enable clinicians to risk-stratify and appropriately implement surveillance strategies to prevent these complications of hepatitis B.

The COVID Positive Pathway: a collaboration between public health agencies, primary care, and metropolitan hospitals in Melbourne.

OBJECTIVES: To assess the capacity of the COVID Positive Pathway, a collaborative model of care involving the Victorian public health unit, hospital services, primary care, community organisations, and the North Western Melbourne Primary Health Network, to support people with coronavirus disease 2019 (COVID-19) isolating at home. DESIGN, SETTING, PARTICIPANTS: Cohort study of adults in northwest Melbourne with COVID-19, 3 August - 31 December 2020. MAIN OUTCOME MEASURES: Demographic and clinical characteristics, and social and welfare needs of people cared for in the Pathway, by care tier level. RESULTS: Of 1392 people referred to the Pathway by the public health unit, 858 were eligible for enrolment, and 711 consented to participation; 647 (91%) remained in the Pathway until they had recovered and isolation was no longer required. A total of 575 participants (81%) received care in primary care, mostly from their usual general practitioners; 155 people (22%) received care from hospital outreach services, and 64 (9%) needed high tier care (hospitalisation). Assistance with food and other basic supplies was required by 239 people in the Pathway (34%). CONCLUSIONS: The COVID Positive Pathway is a feasible multidisciplinary, tiered model of care for people with COVID-19. About 80% of participants could be adequately supported by primary care and community organisations, allowing hospital services to be reserved for people with more severe illness or with risk factors for disease progression. The principles of this model could be applied to other health conditions if regulatory and funding barriers to information-sharing and care delivery by health care providers can be overcome.

Performance of hospital-based contact tracing for COVID-19 during Australia's second wave.

BACKGROUND: Hospital-based contact tracing aims to limit spread of COVID-19 within healthcare facilities. In large outbreaks, this can stretch resources and workforce due to quarantine of uninfected staff. We analysed the performance of a manual contact tracing system for healthcare workers (HCW) at a multi-site healthcare facility in Melbourne, Australia, from June-September 2020, during an epidemic of COVID-19. METHODS: All HCW close contacts were quarantined for 14 days, and tested around day 11, if not already diagnosed with COVID-19. We examined the prevalence and timing of symptoms in cases detected during quarantine, described this group as proportions of all close contacts and of all cases, and used logistic regression to assess factors associated with infection. RESULTS: COVID-19 was diagnosed during quarantine in 52 furloughed HCWs, from 483 quarantine episodes (11%), accounting for 19% (52/270) of total HCW cases. In 361 exposures to a clear index case, odds of infection were higher after contact with an infectious patient compared to an infectious HCW (aOR: 4.69, 95% CI: 1.98-12.14). Contact with cases outside the workplace increased odds of infection compared to workplace contact only (aOR: 7.70, 95% CI: 2.63-23.05). We estimated 30%, 78% and 95% of symptomatic cases would develop symptoms by days 3, 7, and 11 of quarantine, respectively. CONCLUSION: In our setting, hospital-based contact tracing detected and contained a significant proportion of HCW cases, without excessive quarantine of uninfected staff. Effectiveness of contact tracing is determined by a range of dynamic factors, so system performance should be monitored in real-time.

The price tag of a potential cure for chronic hepatitis B infection: A cost threshold analysis for USA, China and Australia.

BACKGROUND & AIMS: We aim to capture the economic impact of a potential cure for chronic hepatitis B infection (CHB) in three countries (USA, China and Australia) with different health systems and epidemics to estimate the threshold drug prices below which a CHB cure would be cost-saving and/or highly cost-effective. METHODS: We simulated patients' hepatitis B progression, under three scenarios: current long-term suppressive antiviral therapy, functional cure defined as sustained undetectable HBsAg and HBV DNA, and partial cure defined as sustained undetectable HBV DNA only after a finite, 48-week treatment. RESULTS: Compared with current long-term antiviral therapy, a 30% effective functional cure among patients with and without cirrhosis in the USA, China and Australia would yield 17.50, 17.32 and 20.42 QALYs per patient, and 20.61, 20.42 and 20.62 QALYs per patient respectively. In financial terms, for CHB patients with and without cirrhosis, this would be cost-saving at a one-time treatment cost under US$11 944 and US$6694, respectively, in the USA, US$1744 and US$1001 in China, and US$12 063 and US$10 983 in Australia. CONCLUSION: We show that in purely economic terms, a CHB cure will be highly cost-effective even if effective in only 30% of treated patients. The threshold price for cure is largely determined by the current antiviral drug costs, since it will replace a daily antiviral pill that is inexpensive and effective, although not curative. The likely need for combination therapies to achieve cure will also present cost challenges. While cost-effectiveness is important, it cannot be the only consideration, as cure will provide many benefits in addition to reduced liver disease and HCC, including eliminating the need for a long-term daily pill and reducing stigma often associated with chronic viral infection.

Maternal Vaccination and Infant Influenza and Pertussis.

BACKGROUND AND OBJECTIVES: Infant influenza and pertussis disease causes considerable morbidity and mortality worldwide. We examined the effectiveness of maternal influenza and pertussis vaccines in preventing these diseases in infants. METHODS: This inception cohort study comprised women whose pregnancies ended between September 1, 2015, and December 31, 2017, in Victoria, Australia. Maternal vaccination status was sourced from the Victorian Perinatal Data Collection and linked to 5 data sets to ascertain infant outcomes and vaccination. The primary outcome of interest was laboratory-confirmed influenza or pertussis disease in infants aged <2 months, 2 to <6 months, and <6 months combined. Secondary outcomes included infant hospitalization (emergency presentation or admission) and death. Risk ratios and 95% confidence intervals (CIs) were estimated by Poisson regression. Vaccine effectiveness (VE) was estimated as (1 minus the risk ratio) x 100%. RESULTS: Among 186 962 pregnant women, 85 830 (45.9%) and 128 060 (68.5%) were vaccinated against influenza and pertussis, respectively. There were 175 and 51 infants with laboratory-confirmed influenza and pertussis disease, respectively. Influenza VE was 56.1% (95% CI, 23.3% to 74.9%) for infants aged <2 months and 35.7% (2.2% to 57.7%) for infants aged 2 to <6 months. Pertussis VE was 80.1% (95% CI, 37.1% to 93.7%) for infants aged <2 months and 31.8% (95% CI, -39.1% to 66.6%) for infants aged 2 to <6 months. CONCLUSIONS: Our study provides evidence of the direct effectiveness of maternal influenza and pertussis vaccination in preventing these diseases in infants aged <2 months. The findings strengthen the importance of maternal vaccination to prevent these diseases in infants.

Clinical presentation and management of COVID-19.

The rapid spread of severe acute respiratory syndrome coronavirus 2 led to the declaration of a global pandemic within 3 months of its emergence. The majority of patients presenting with coronavirus disease 2019 (COVID-19) experience a mild illness that can usually be managed in the community. Patients require careful monitoring and early referral to hospital if any signs of clinical deterioration occur. Increased age and the presence of comorbidities are associated with more severe disease and poorer outcomes. Treatment for COVID-19 is currently predominantly supportive care, focused on appropriate management of respiratory dysfunction. Clinical evidence is emerging for some specific therapies (including antiviral and immune-modulating agents). Investigational therapies for COVID-19 should be used in the context of approved randomised controlled trials. Australian clinicians need to be able to recognise, diagnose, manage and appropriately refer patients affected by COVID-19, with thousands of cases likely to present over the coming years.

Adherence in chronic hepatitis B: associations between medication possession ratio and adverse viral outcomes.

BACKGROUND: Antiviral therapy for chronic hepatitis B (CHB) is effective and can substantially reduce the risk of progressive liver disease and hepatocellular carcinoma but is often administered for an indefinite duration. Adherence has been shown in clinical trials to maximize the benefit of therapy and prevent the development of resistance, however the optimal threshold for predicting clinical outcomes has not been identified. The aim of this study was to analyse adherence using the medication possession ration (MPR) and its relation to virological outcomes in a large multi-centre hospital outpatient population, and guide development of an evidence-based threshold for optimal adherence. METHODS: Pharmacy and pathology records of patients dispensed CHB antiviral therapy from 4 major hospitals in Melbourne between 2010 and 2013 were extracted and analysed to determine their MPR and identify instances of unfavourable viral outcomes. Viral outcomes were classified categorically, with unfavourable outcomes including HBV DNA remaining detectable after 2 years treatment or experiencing viral breakthrough. The association between MPR and unfavourable outcomes was assessed according to various thresholds using ROC analysis and time-to-event regression. RESULTS: Six hundred forty-two individuals were included in the analysis. Median age was 46.6 years, 68% were male, 77% were born in Asia, and the median time on treatment was 27.5 months. The majority had favourable viral outcomes (91.06%), with most having undetectable HBV DNA at the end of the study period. The most common unfavourable outcome was a rise of < 1 log in HBV DNA (6.54% of the total), while 2.49% of participants experienced viral breakthrough. Adherence was linearly associated with favourable outcomes, with increasing risk of virological breakthrough as MPR fell. Decreasing the value of MPR, at which a cut-point was taken, was associated with a progressively larger reduction in the rate of unfavourable event; from a 60% reduction under a cut-point of 1.00 to a 79% reduction when the MPR cut-point was set at 0.8. CONCLUSION: Lower adherence as measured using the MPR was strongly associated with unfavourable therapeutic outcomes, including virological failure. Optimising adherence is therefore important for preventing viral rebound and potential complications such as antiviral resistance. The evidence of dose-response highlights the need for nuanced interventions.

'Think Hep B' in primary care: A before-and-after evaluation of a self-guided learning package.

BACKGROUND AND OBJECTIVES: In Australia, over a third of individuals living with chronic hepatitis B (CHB) remain undiagnosed. Evidence suggests general practitioners (GPs) can be uncertain regarding whom to test. The aim of this study was to evaluate an educational resource for improving GPs' knowledge about whom to test for CHB. METHOD: Following a 2014 baseline survey that identified gaps in CHB knowledge among GPs in Victoria, an educational resource package was developed. Using a follow-up survey, the resource was evaluated by comparing the before-and-after CHB-related knowledge. RESULTS: Sixty-five GPs responded to both the baseline and follow-up survey. Their knowledge of populations at high risk of CHB who require testing was significantly greater following the intervention than at baseline. DISCUSSION: Concise, clear and practical resources can support GPs when identifying whom to test for hepatitis B.