Immunogenicity of a single fractional intradermal dose of Japanese encephalitis live attenuated chimeric vaccine

BACKGROUND

Japanese encephalitis (JE) is endemic in Asia and the western Pacific. Vaccination is recommended for travellers to endemic regions, but the high cost of the vaccine is a major barrier to uptake.

METHODS

A quasi-experimental, pre-post intervention clinical trial without a control group was conducted to assess the immunogenicity and safety of intradermal (ID) JE vaccine. Healthy adults (18-45 years) received one dose of 0.1 mL (20% of standard dose) ID Imojev® (JE live attenuated chimeric vaccine, Sanofi-Aventis). Adverse events following immunisation (AEFIs) were recorded 10 days post-vaccination. Blood samples were collected at baseline, 4, and 8 weeks post-vaccination. Neutralising antibodies were measured using 50% plaque reduction neutralisation test (PRNT50). Seroconversion was defined as PRNT50 titre ≥10. An in vitro study was also conducted to quantify the rate of decay of vaccine potency after reconstitution.

RESULTS

51 participants (72.6% females, median age 31 years), all non-reactive to JE virus at baseline were enrolled. Mild and moderate AEFIs were reported by 19.6% of participants; none required medical attention or interfered with normal daily activities. All participants seroconverted at 4 weeks (GMT 249.3; 95%CI:192.8-322.5) and remained seropositive at 8-weeks (GMT 135.5; 95%CI:104.5-175.6). Vaccine potency declined at a rate of 0.14 log plaque-forming units/0.5 mL per hour.

CONCLUSIONS

In healthy adults, a single 0.1 mL ID dose of Imojev was safe and immunogenic, at least in the short-term. Reconstituted vials of Imojev vaccine may not retain their potency after 6 hours. Fractional JE ID vaccination could be a cheaper yet effective alternative for short-term travellers. Further studies need to investigate the immune response in a wider age range of individuals and the long-term immunogenicity of fractional JE ID vaccines.

CLINICAL TRIALS REGISTRATION

ACTRN12621000024842.

Epidemiology of cruciate ligament reconstruction in the Australian Defence Force and predictors of outcome

BACKGROUND

The ability to predict the risk of poor outcome following knee cruciate ligament reconstruction in the Australian Defence Force (ADF) population would help direct individual rehabilitation programmes and workforce planning. This study describes the epidemiology of cruciate ligament reconstruction in the ADF and demonstrates the use of Bayesian networks (BN) to predict the likelihood of fitness for ongoing service under different scenarios.

METHODS

Members who had knee cruciate ligament reconstruction through ADF were identified from billing data and matched to electronic medical records to extract demographic and clinical data. Outcome measure was medical fitness for ADF service up to 24 months after reconstruction. BN models were used to compare outcomes between (1) age groups according to military service, and (2) sexes according to body mass index (BMI).

RESULTS

From November 2012 to June 2019, a total of 1199 individuals had knee cruciate ligament reconstruction (average 169 reconstructions/year). Following reconstruction and rehabilitation, 89 (7.4%) were medically unfit for service. Scenario analysis using a tree-augmented naïve BN model showed that, compared with Navy and Air Force, Army members had a higher probability of being unfit in those aged <35 years and a lower probability in those aged ≥35 years. In both sexes, those with obese BMI had the greatest probability of being unfit.

CONCLUSION

While most ADF members were fit for ongoing military service following cruciate ligament reconstruction, service type, age, sex and BMI influenced outcome. BNs provided an interactive and intuitive method to demonstrate the impact of different variables on the outcome.

Assessment of Environmental Impacts on Health: Examples from the Pacific Basin

Assessing environmental impacts on health in the Pacific Basin is challenged by significantly varying data types - quantities, qualities, and paucities - because of varying geographic sizes, environments, biodiversity, ecological assets, and human population densities, with highly varied and unequal socio-economic development and capacity to respond to environmental and health challenges. We discuss three case-based methodological examples from Pacific Basin environmental health impact assessments. These methods could be used to improve environmental health evidence at all country and regional levels across a spectrum of big data availability to no data. These methods are, 1) a risk assessment of airborne particulate matter in Korea based on the chemical composition of these particulates; 2) the use of system dynamics to appraise the influences of a range of environmental health determinants on child health outcomes in remote Solomon Islands; and 3) precision environmental public health methodologies based on comprehensive data collection, analyses, and modelling (including Bayesian belief networks and spatial epidemiology) increasing precision for good environmental health decision making to prevent and control a zoonotic disease in Fiji Islands. We show that while a common theme across the three examples is the value of high quality and quantity data to support stronger policy decisions and appropriate prioritizing of investment, it is also clear that for many countries in the Pacific Basin, sufficient data will remain a challenge to inform decision makers about environmental impact on health.

A Bayesian network analysis quantifying risks versus benefits of the Pfizer COVID-19 vaccine in Australia

The Pfizer COVID-19 vaccine is associated with increased myocarditis incidence. Constantly evolving evidence regarding incidence and case fatality of COVID-19 and myocarditis related to infection or vaccination, creates challenges for risk-benefit analysis of vaccination. Challenges are complicated further by emerging evidence of waning vaccine effectiveness, and variable effectiveness against variants. Here, we build on previous work on the COVID-19 Risk Calculator (CoRiCal) by integrating Australian and international data to inform a Bayesian network that calculates probabilities of outcomes for the delta variant under different scenarios of Pfizer COVID-19 vaccine coverage, age groups (≥12 years), sex, community transmission intensity and vaccine effectiveness. The model estimates that in a population where 5% were unvaccinated, 5% had one dose, 60% had two doses and 30% had three doses, there was a substantially greater probability of developing (239–5847 times) and dying (1430–384,684 times) from COVID-19-related than vaccine-associated myocarditis (depending on age and sex). For one million people with this vaccine coverage, where transmission intensity was equivalent to 10% chance of infection over 2 months, 68,813 symptomatic COVID-19 cases and 981 deaths would be prevented, with 42 and 16 expected cases of vaccine-associated myocarditis in males and females, respectively. These results justify vaccination in all age groups as vaccine-associated myocarditis is generally mild in the young, and there is unequivocal evidence for reduced mortality from COVID-19 in older individuals. The model may be updated to include emerging best evidence, data pertinent to different countries or vaccines and other outcomes such as long COVID.

Molecular characterisation of Neisseria gonorrhoeae associated with disseminated gonococcal infections in Queensland, Australia: a retrospective surveillance study

OBJECTIVES

Gonorrhoea caused by Neisseria gonorrhoeae is the second most notified sexually transmitted infection (STI) in Australia and the case numbers for this STI have been increasing globally. Progressive gonococcal infection may lead to disseminated gonococcal infection (DGI), which causes significant morbidity among patients. This study aims to examine the genetic diversity of N. gonorrhoeae isolates collected in Queensland from January 2010 to August 2015 and to determine factors associated with DGI in Queensland.

DESIGN

Retrospective surveillance study for epidemiological purposes.

SETTING

All gonorrhoeae isolates referred by private and public pathology laboratories to the state of Queensland, Australia Neisseria reference laboratory.

METHODS

Between January 2010 and August 2015, 3953 N. gonorrhoeae isolates from both metropolitan and regional Queensland infections were typed with NG-MAST (N. gonorrhoeae multiantigen sequence typing) to assess the genetic diversity between strains. Whole-genome sequencing (WGS) was used to investigate strain-related factors associated with DGI.

RESULTS

ST6876 was the most common NG-MAST type, detected in 7.6% of the isolates. DGI was significantly more likely in females <30 years (OR 13.02, p<0.0001) and in older males >30 years (OR 6.04, p<0.0001), with most cases originating from North Queensland (OR 8.5, p<0.0001). Strains harbouring PIA class of porB type were associated with DGI (OR 33.23, p<0.0001).

CONCLUSION

Genotyping techniques, such as NG-MAST and WGS, are proving instrumental in providing an insight into the population structure of N. gonorrhoeae, and genetic mechanisms of pathogenesis, such as for DGI.

The risk factors for complications and survival outcomes of Klebsiella pneumoniae Bacteraemia in Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia

INTRODUCTION

Mortality of Klebsiella pneumoniae (K. pneumoniae) bacteraemia was reported to be on the rise globally. The 30-day mortality rate of K. pneumoniae bacteraemia ranges from 16% to 55% in Beijing, Shanghai, and Taiwan. However, there is a lack of research on the survival outcomes of K. pneumoniae bacteraemia in Malaysia. The objectives of this study were to determine the poor prognostic factors and predictors of 14-day in-hospital mortality from K. pneumoniae bacteraemia.

METHODS

This was a retrospective cohort study of patients with K. pneumoniae bacteraemia in Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia (HCTM). We included adult patients with blood cultures positive for K. pneumoniae between 1 January 2016 and 31 December 2019. Those with polymicrobial bacteraemia were excluded. Medical records were reviewed to obtain the sociodemographic data, gender, underlying comorbidities, invasive procedures at presentation, sources of bacteraemia, and whether appropriate empirical and definitive antibiotics was given on time. Data regarding complications of K. pneumoniae bacteraemia, including liver abscess, endopthalmitis, septic shock, Quick Pitt (qPitt) bacteraemia score defined as hypothermia, hypotension, respiratory failure, cardiac arrest, and altered mental status and stay in intensive care unit (ICU) were also recorded. The main outcome measure used was the survival in 14 days. Summary of statistical analysis was done.

RESULTS

A total of 260 patients with K. pneumoniae bacteraemia were included. All patients received appropriate empirical and definitive antibiotics within 24 h of the time that the sample for index blood cultures was obtained. Respiratory infection, septic shock, qPitt bacteraemia score ≥2, solid organ malignancy, stay in ICU, central venous line insertion at presentation, urinary catheterisation at presentation, and in-patient mechanical ventilation were identified as independent predictors of mortality in K. pneumoniae bacteraemia. The rate of complications such as liver abscess, endophthalmitis, ICU admission, and septic shock was not significantly different between survivors and non-survivors. The 14-day in-hospital mortality rate was 12.3%. The median length of hospitalisation was 11 days (IQR 6 - 19) . The predictors of poor prognosis for 14 days in-hospital mortality for K. pneumoniae bacteraemia were as follows: qPitt bacteraemia score ≥2, central venous line insertion, indwelling urinary catheter at presentation, and in-patient mechanical ventilation. Timing from K. pneumoniae bacteraemia event to death among those qPitt bacteraemia scores ≥2 was only for 9 days or less.

CONCLUSIONS

The 14-day in-hospital mortality of patients with K. pneumoniae bacteraemia in our setting was low. The qPitt bacteraemia score ≥2 was the strongest predictor of poor prognosis for 14-day in-hospital mortality in patients with K. pneumoniae bacteraemia. The qPitt bacteraemia score should be proposed to be used as a bedside screening tool for gram negative bacteraemia in our daily clinical practice, which is also useful for predicting mortality in critically ill patients.

Estimating the duration of antibody positivity and likely time of Leptospira infection using data from a cross-sectional serological study in Fiji

Background

Leptospirosis is a zoonotic disease prevalent throughout the world, but with particularly high burden in Oceania (including the Pacific Island Countries and Territories). Leptospirosis is endemic in Fiji, with outbreaks often occurring following heavy rainfall and flooding. As a result of non-specific clinical manifestation and diagnostic challenges, cases are often misdiagnosed or under-ascertained. Furthermore, little is known about the duration of persistence of antibodies to leptospirosis, which has important clinical and epidemiological implications.

Methodology and principal findings

Using the results from a serosurvey conducted in Fiji in 2013, we fitted serocatalytic models to estimate the duration of antibody positivity and the force of infection (FOI, the rate at which susceptible individuals acquire infection or seroconversion), whilst accounting for seroreversion. Additionally, we estimated the most likely timing of infection.

Using the reverse catalytic model, we estimated the duration of antibody persistence to be 8.33 years (4.76–12.50; assuming constant FOI) and 7.25 years (3.36–11.36; assuming time-varying FOI), which is longer than previous estimates. Using population age-structured seroprevalence data alone, we were not able to distinguish between these two models. However, by bringing in additional longitudinal data on antibody kinetics we were able to estimate the most likely time of infection, lending support to the time-varying FOI model. We found that most individuals who were antibody-positive in the 2013 serosurvey were likely to have been infected within the previous two years, and this finding is consistent with surveillance data showing high numbers of cases reported in 2012 and 2013.

Conclusions

This is the first study to use serocatalytic models to estimate the FOI and seroreversion rate for Leptospira infection. As well as providing an estimate for the duration of antibody positivity, we also present a novel method to estimate the most likely time of infection from seroprevalence data. These approaches can allow for richer, longitudinal information to be inferred from cross-sectional studies, and could be applied to other endemic diseases where antibody waning occurs.

Leptospirosis is a bacterial zoonotic disease that occurs in almost all regions of the world, with a particularly high burden of disease in Oceania. It is widely considered to be a Neglected Zoonotic Disease, and it is often mis-diagnosed and under-ascertained. Very little information exists about the persistence of antibodies to leptospirosis, which is important for understanding how long individuals may have partial protection against reinfection. In this study, we show how data collected from a large population survey of leptospirosis antibodies can be used to estimate the duration of antibody persistence. Knowledge of the duration of antibody persistence enables an estimation of the duration of immunity to re-infection, which is most likely antibody-mediated. We also estimate the rate at which susceptible individuals acquire infection (force of infection), whilst accounting for antibody waning. This provides more accurate estimates of population-wide disease burden. Finally, we show how the results from a cross-sectional population survey can be used to estimate when infections may have occurred. This is particularly useful in areas with limited surveillance. This approach could be applied to other neglected diseases for which data are limited and where antibody waning occurs.

The Emergence of Japanese Encephalitis in Australia and the Implications for a Vaccination Strategy

Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. Until 2022, only six locally transmitted human JE cases had been reported in Australia; five in northern Queensland and one in the Northern Territory. Thus, JE was mainly considered to be a disease of travellers. On 4 March 2022, JE was declared a ‘Communicable Disease Incident of National Significance’ when a locally acquired human case was confirmed in southern Queensland. By 11 May 2022, 41 human JE cases had been notified in four states in Australia, in areas where JE has never been detected before. From this perspective, we discuss the potential reasons for the recent emergence of the JE virus in Australia in areas where JE has never been previously reported as well as the implications of and options for mass immunisation programs if the outbreak escalates in a JE virus-immunologically naïve population.

Persistence of antibodies, boostability, and interchangeability of Japanese encephalitis vaccines: A systematic review and dose-response meta-analysis

BACKGROUND

The burden of Japanese encephalitis (JE) is substantial and is arguably one of the most serious viral encephalitic diseases with high case fatality and no specific treatment. JE vaccines are the only available mean to prevent the disease; however, the long-term persistence of antibodies, boostability, and interchangeability between different vaccine classes are not well understood.

METHODS

To summarise the evidence, PubMed, Embase, and Cochrane CENTRAL were systematically searched from their inception to March 2021. Dose-response meta-analysis was utilised to synthesise the proportion of individuals who were seropositive over time after a primary vaccination course and a booster dose. Proportion meta-analysis was conducted to estimate the proportion of individuals who were seropositive as well as those who reported adverse events following a booster dose with a different vaccine class.

RESULTS

Of 1053 publications retrieved, 27 studies with 4,558 participants were included. Of these, 11 studies assessed persistence of antibodies, 14 studies boostability, and 8 vaccine class interchangeability. The pooled seropositivity, 1-year after primary vaccination was 83.4% (95 %CI 78.2-89.5%) and remained stable for up to 5 years (82.7%; 95 %CI 76.1-89.4%). Rapid anamnestic response was observed 10 days post-booster dose, the proportion of individuals who were seropositive reached 96.9% (95 %CI 95.9-97.8%) and remained > 95% for up to 6 years. Inactivated mouse brain-derived vaccines followed by a booster dose of a different vaccine class was effective (i.e. seropositive 99%) and well tolerated.

CONCLUSIONS

A booster dose after the primary vaccination is effective and further booster doses may be needed after 7 years. Inactivated mouse brain-derived vaccine followed by a booster with a newer vaccine class is effective and safe; although, there is a paucity of data related to newer classes of vaccines interchangeability.

Hospitalisation with injection-related infections: Validation of diagnostic codes to monitor admission trends at a tertiary care hospital in Melbourne, Australia

INTRODUCTION

Injection-related infections (IRI) cause morbidity and mortality in people who inject drugs. Hospital administrative datasets can be used to describe hospitalisation trends, but there are no validated algorithms to identify injecting drug use and IRIs. We aimed to validate International Classification of Diseases (ICD) codes to identify admissions with IRIs and use these codes to describe IRIs within our hospital.

METHODS

We developed a candidate set of ICD codes to identify current injecting drug use and IRI and extracted admissions satisfying both criteria. We then used manual chart review data from 1 January 2017 to 30 April 2019 to evaluate the performance of these codes and refine our algorithm by selecting codes with a high-positive predictive value (PPV). We used the refined algorithm to describe trends and outcomes of people who inject drugs with an IRI at Alfred Hospital, Melbourne from 2008 to 2020.

RESULTS

Current injecting drug use was best predicted by opioid-related disorders (F11), 80% (95% confidence interval [CI] 74-85%), and other stimulant-related disorders (F15), 82% (95% CI 70-90%). All PPVs were ≥67% to identify specific IRIs, and ≥84% for identifying any IRI. Using these codes over 12 years, IRIs increased from 138 to 249 per 100 000 admissions, and skin and soft tissues infections (SSTI) were the most common (797/1751, 46%).

DISCUSSION AND CONCLUSION

Validated ICD-based algorithms can inform passive surveillance systems. Strategies to reduce hospitalisation with IRIs should be supported by early intervention and prevention, particularly for SSTIs which may represent delayed access to care.

Designing an evidence-based Bayesian network for estimating the risk versus benefits of AstraZeneca COVID-19 vaccine

Uncertainty surrounding the risk of developing and dying from Thrombosis and Thrombocytopenia Syndrome (TTS) associated with the AstraZeneca (AZ) COVID-19 vaccine may contribute to vaccine hesitancy. A model is urgently needed to combine and effectively communicate evidence on the risks versus benefits of the AZ vaccine. We developed a Bayesian network to consolidate evidence on risks and benefits of the AZ vaccine, and parameterised the model using data from a range of empirical studies, government reports, and expert advisory groups. Expert judgement was used to interpret the available evidence and determine the model structure, relevant variables, data for inclusion, and how these data were used to inform the model.

The model can be used as a decision-support tool to generate scenarios based on age, sex, virus variant and community transmission rates, making it useful for individuals, clinicians, and researchers to assess the chances of different health outcomes. Model outputs include the risk of dying from TTS following the AZ COVID-19 vaccine, the risk of dying from COVID-19 or COVID-19-associated atypical severe blood clots under different scenarios. Although the model is focused on Australia, it can be adapted to international settings by re-parameterising it with local data. This paper provides detailed description of the model-building methodology, which can be used to expand the scope of the model to include other COVID-19 vaccines, booster doses, comorbidities and other health outcomes (e.g., long COVID) to ensure the model remains relevant in the face of constantly changing discussion on risks versus benefits of COVID-19 vaccination.

Lymphatic filariasis in 2016 in American Samoa: Identifying clustering and hotspots using non-spatial and three spatial analytical methods

Background

American Samoa completed seven rounds of mass drug administration from 2000–2006 as part of the Global Programme to Eliminate Lymphatic Filariasis (LF). However, resurgence was confirmed in 2016 through WHO-recommended school-based transmission assessment survey and a community-based survey. This paper uses data from the 2016 community survey to compare different spatial and non-spatial methods to characterise clustering and hotspots of LF.

Method

Non-spatial clustering of infection markers (antigen [Ag], microfilaraemia [Mf], and antibodies (Ab [Wb123, Bm14, Bm33]) was assessed using intra-cluster correlation coefficients (ICC) at household and village levels. Spatial dependence, clustering and hotspots were examined using semivariograms, Kulldorf’s scan statistic and Getis-Ord Gi* statistics based on locations of surveyed households.

Results

The survey included 2671 persons (750 households, 730 unique locations in 30 villages). ICCs were higher at household (0.20–0.69) than village levels (0.10–0.30) for all infection markers. Semivariograms identified significant spatial dependency for all markers (range 207–562 metres). Using Kulldorff’s scan statistic, significant spatial clustering was observed in two previously known locations of ongoing transmission: for all markers in Fagali’i and all Abs in Vaitogi. Getis-Ord Gi* statistic identified hotspots of all markers in Fagali’i, Vaitogi, and Pago Pago-Anua areas. A hotspot of Ag and Wb123 Ab was identified around the villages of Nua-Seetaga-Asili. Bm14 and Bm33 Ab hotspots were seen in Maleimi and Vaitogi-Ili’ili-Tafuna.

Conclusion

Our study demonstrated the utility of different non-spatial and spatial methods for investigating clustering and hotspots, the benefits of using multiple infection markers, and the value of triangulating results between methods.

Long-term persistence of antibodies and boostability after rabies intradermal pre-exposure prophylaxis

BACKGROUND

Currently, there is limited data on long-term persistence of antibodies and boostability of intradermal (ID) rabies pre-exposure prophylaxis (PrEP) schedules. This study investigated travellers who received a primary ID PrEP schedule at least 5 years previously to determine the persistence of antibodies and subsequent antibody response after one 0.1-ml ID booster dose.

METHODS

Adults (age ≥ 18 years) who had previously received ID PrEP at a specialist travel medicine clinic in Brisbane, Australia were included. At Day 0, blood was collected for serology and one dose of 0.1-ml ID rabies vaccine (Verorab®) was administered. At Day 7, serology was repeated. At Day 14, participants were given results and enquired if they experienced adverse events following immunization (AEFIs). Antibodies were measured using Platelia Rabies II ELISA; levels ≥0.5 EU/mL were considered antibody-positive.

RESULTS

158 participants were included [64.6% female, median age at enrolment 56.4 years, interquartile range (IQR) 42.4-65.2 years], and median time since the primary ID PrEP was 8.5 years (IQR 6.9-11.7 years). The majority of participants (82.3%) were antibody-positive at Day 0. The proportion of participants who were antibody-positive at Day 0 was higher among those who were younger at primary vaccination (87.0% if aged<50 years, 75.8% of aged ≥50 years). The proportion of participants who were antibody-positive declined as median time since primary vaccination increased, though the trend was not statistically significant (p-trend = 0.187). All except one participant (99.4%) were antibody-positive after one ID booster dose. AEFIs were reported by 42.4% of participants and were mainly mild.

CONCLUSIONS

Rabies antibodies persist for many years after ID PrEP and can be rapidly boosted with a single ID dose. Future studies are needed to confirm that ID PrEP primes the immune system sufficiently so that boosters are not routinely needed, and only given in the event of a rabies-prone exposure.

Potential use of antibodies to provide an earlier indication of lymphatic filariasis resurgence in post-mass drug administration surveillance, American Samoa

OBJECTIVES

Under the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted seven rounds of mass drug administration between 2000 and 2006. The territory passed transmission assessment surveys (TAS) in 2011 (TAS-1) and 2015 (TAS-2). In 2016, the territory failed TAS-3, indicating resurgence. This study aims to determine if antibodies (Ab) may have provided a timelier indication of LF resurgence in American Samoa.

METHODS

We examined school-level antigen (Ag) and Ab status (presence/absence of Ag- and Ab-positive children) and prevalence of single and combined Ab responses to Wb123, Bm14, Bm33 Ags at each TAS. Pearson's chi-squared tests and logistic regression were used to examine associations between school-level Ab prevalence in TAS-1 and TAS-2 and school-level Ag status in TAS-3.

RESULTS

Schools with higher prevalence of Wb123 Ab in TAS-2 had higher odds of being Ag-positive in TAS-3 (odds ratio [OR] 24.5, 95% CI:1.2-512.7). Schools that were Ab-positive for WB123 plus Bm14, Bm33 or both Bm14 and Bm33 in TAS-2 had higher odds of being Ag-positive in TAS-3 (OR 16.0-24.5).

CONCLUSION

Abs could provide earlier signals of resurgence and enable a timelier response. The promising role of Abs in post-mass drug administration (MDA) surveillance and decision making should be further investigated in other settings.

Risk-benefit analysis of COVID-19 vaccines - a neurological perspective

Rare neurological complications can occur after COVID-19 vaccination, but recent studies show that such complications are much more common after SARS-CoV-2 infection. Novel approaches to risk–benefit analysis such as Bayesian network models can integrate the latest global evidence with local factors to inform decision-making and support the global vaccination effort.

High rate of asymptomatic colonization with antimicrobial-resistant Escherichia coli in Australian returned travellers

Global movement of people plays a key role in the spread of antimicrobial resistant (AMR) organisms. We found that 58% of Australian travellers returning from Asia were asymptomatic carriers of AMR Escherichia coli, including resistance to critically important antibiotics. Future studies are needed to identify interventions for travellers to reduce their risk of AMR acquisition.

Risk-benefit analysis of the AstraZeneca COVID-19 vaccine in Australia using a Bayesian network modelling framework

Thrombosis and Thrombocytopenia Syndrome (TTS) has been associated with the AstraZencea (AZ) COVID-19 vaccine (Vaxzevria). Australia has reported low TTS incidence of < 3/100,000 after the first dose, with case fatality rate (CFR) of 5-6%. Risk-benefit analysis of vaccination has been challenging because of rapidly evolving data, changing levels of transmission, and variation in rates of TTS, COVID-19, and CFR between age groups. We aim to optimise risk-benefit analysis by developing a model that enables inputs to be updated rapidly as evidence evolves. A Bayesian network was used to integrate local and international data, government reports, published literature and expert opinion. The model estimates probabilities of outcomes under different scenarios of age, sex, low/medium/high transmission (0.05%/0.45%/5.76% of population infected over 6 months), SARS-CoV-2 variant, vaccine doses, and vaccine effectiveness. We used the model to compare estimated deaths from AZ vaccine-associated TTS with i) COVID-19 deaths prevented under different scenarios, and ii) deaths from COVID-19 related atypical severe blood clots (cerebral venous sinus thrombosis & portal vein thrombosis). For a million people aged ≥ 70 years where 70% received first dose and 35% received two doses, our model estimated < 1 death from TTS, 25 deaths prevented under low transmission, and > 3000 deaths prevented under high transmission. Risks versus benefits varied significantly between age groups and transmission levels. Under high transmission, deaths prevented by AZ vaccine far exceed deaths from TTS (by 8 to > 4500 times depending on age). Probability of dying from COVID-related atypical severe blood clots was 58-126 times higher (depending on age and sex) than dying from TTS. To our knowledge, this is the first example of the use of Bayesian networks for risk-benefit analysis for a COVID-19 vaccine. The model can be rapidly updated to incorporate new data, adapted for other countries, extended to other outcomes (e.g., severe disease), or used for other vaccines.

Development of the COVID-19 Real-Time Information System for Preparedness and Epidemic Response (CRISPER), Australia

Accurate and current information has been highlighted across the globe as a critical requirement for the COVID-19 pandemic response. To address this need, many interactive dashboards providing a range of different information about COVID-19 have been developed. A similar tool in Australia containing current information about COVID-19 could assist general practitioners and public health responders in their pandemic response efforts. The COVID-19 Real-time Information System for Preparedness and Epidemic Response (CRISPER) has been developed to provide accurate and spatially explicit real-time information for COVID-19 cases, deaths, testing and contact tracing locations in Australia. Developed based on feedback from key users and stakeholders, the system comprises three main components: (1) a data engine; (2) data visualization and interactive mapping tools; and (3) an automated alert system. This system provides integrated data from multiple sources in one platform which optimizes information sharing with public health responders, primary health care practitioners and the general public.

Managing the Digital Disruption Associated with COVID-19-Driven Rapid Digital Transformation in Brisbane, Australia

BACKGROUND

The COVID-19 pandemic has forced rapid digital transformation of many health systems. These innovations are now entering the literature, but there is little focus on the resulting disruption.

OBJECTIVE

We describe the implementation of digital innovations during the COVID-19 response of Australia's largest health service, Metro North (in Brisbane, Queensland), the challenges of the subsequent digital disruption, how these were managed, and lessons learned.

METHODS

Prior to the COVID-19 pandemic, the Australian state of Queensland created the Queensland Digital Clinical Charter, which provides guidance for the development of digital health programs. The guidelines utilize three horizons: digitizing workflows, leveraging digital data to transform clinical care, and reimagining new and innovative models of care. The technical response to COVID-19 in Metro North is described across these horizons. The rapid digital response caused significant disruption to health care delivery; management of the disruption and the outcomes are detailed. This is a participatory action research project, with members of the research team assisting with leading the implementation project informing the case report content.

RESULTS

Several digital innovations were introduced across Metro North during the COVID-19 response. This resulted in significant disruption creating digital hypervigilance, digital deceleration, data discordance, and postdigital "depression." Successful management of the digital disruption minimized the negative effects of rapid digital transformation, and contributed to the effective management of the pandemic in Queensland.

CONCLUSION

The rapid digital transformation in Metro North during COVID-19 was successful in several aspects; however, ongoing challenges remain. These include the need to improve data sharing and increase interoperability. Importantly, the innovations need to be evaluated to ensure that Metro North can capitalize on these changes and incorporate them into long-term routine practice. Moving forward, it will be essential to manage not only the pandemic, but increasingly, the resultant digital disruption.

Differential privacy for public health data: An innovative tool to optimize information sharing while protecting data confidentiality

Coronavirus disease 2019 (COVID-19) has highlighted the need for the timely collection and sharing of public health data. It is important that data sharing is balanced with protecting confidentiality. Here we discuss an innovative mechanism to protect health data, called differential privacy. Differential privacy is a mathematically rigorous definition of privacy that aims to protect against all possible adversaries. In layperson's terms, statistical noise is applied to the data so that overall patterns can be described, but data on individuals are unlikely to be extracted. One of the first use cases for health data in Australia is the development of the COVID-19 Real-Time Information System for Preparedness and Epidemic Response (CRISPER), which provides proof of concept for the use of this technology in the health sector. If successful, this will benefit future sharing of public health data.

Differential privacy is an innovative technique that can be applied to data to protect confidentiality. This has been used primarily to protect private sector data, but has significant implications for public health. We describe the methods of differential privacy in terms understandable to a non-computer-science audience. To our knowledge, this is the first article describing differential privacy in language and context appropriate for a health audience. The case study described shows the feasibility of the use of differential privacy for public health surveillance data to optimize information sharing while protecting data confidentiality. This method allows for data to be released in more granular detail in terms of time, place, and person without compromising privacy and confidentiality. Future research needs to consider other use cases, including a range of surveillance systems and applications in other types of health data.

Control and elimination of lymphatic filariasis in Oceania: Prevalence, geographical distribution, mass drug administration, and surveillance in Samoa, 1998-2017

Lymphatic filariasis (LF) is a major public health problem globally and in the Pacific Region. The Global Programme to Eliminate LF has made great progress but LF is persistent and resurgent in some Pacific countries and territories. Samoa remains endemic for LF despite elimination efforts through multiple two-drug mass drug administrations (MDA) since 1965, including renewed elimination efforts started in 1999 under the Pacific Programme for Elimination of LF (PacELF). Despite eight rounds of national and two rounds of subnational MDA under PacELF, Samoa failed transmission assessment surveys (TAS) in all three evaluation units in 2017. In 2018, Samoa was the first to distribute countrywide triple-drug MDA using ivermectin, diethylcarbamazine (DEC), and albendazole. This paper provides a review of MDAs and historical survey results from 1998 to 2017 in Samoa and highlights lessons learnt from LF elimination efforts, including challenges and potential ways to overcome them to successfully achieve elimination.

Strategies Used for Implementing and Promoting Adherence to Antibiotic Guidelines in Low- and Lower-Middle-Income Countries: A Systematic Review

Containing antimicrobial resistance and reducing high levels of antibiotic consumption in low- and lower middle-income countries are a major challenge. Clinical guidelines targeting antibiotic prescribing can reduce consumption, however, the degrees to which clinical guidelines are adopted and adhered to are challenging for developers, policy makers and users. The aim of this study was to review the strategies used for implementing and promoting antibiotic guideline adherence in low- and lower middle-income countries. A review of published literature was conducted using PubMed, Cochrane Library, SCOPUS and the information systems of the World Health Organization and the Australian National University according to PRISMA guidelines and our PROSPERO protocol. The strategies were grouped into five broad categories based on the Cochrane Effective Practice and Organization of Care taxonomy. The 33 selected studies, representing 16 countries varied widely in design, setting, disease focus, methods, intervention components, outcomes and effects. The majority of interventions were multifaceted and resulted in a positive direction of effect. The nature of the interventions and study variability made it impossible to tease out which strategies had the greatest impact on improving CG compliance. Audit and feedback coupled with either workshops and/or focus group discussions were the most frequently used intervention components. All the reported strategies are established practices used in antimicrobial stewardship programs in high-income countries. We recommend interrupted time series studies be used as an alternative design to pre- and post-intervention studies, information about the clinical guidelines be made more transparent, and prescriber confidence be investigated.

Gram-negative neonatal sepsis in low- and lower-middle-income countries and WHO empirical antibiotic recommendations: A systematic review and meta-analysis

BACKGROUND

Neonatal sepsis is a significant global health issue associated with marked regional disparities in mortality. Antimicrobial resistance (AMR) is a growing concern in Gram-negative organisms, which increasingly predominate in neonatal sepsis, and existing WHO empirical antibiotic recommendations may no longer be appropriate. Previous systematic reviews have been limited to specific low- and middle-income countries. We therefore completed a systematic review and meta-analysis of available data from all low- and lower-middle-income countries (LLMICs) since 2010, with a focus on regional differences in Gram-negative infections and AMR.

METHODS AND FINDINGS

All studies published from 1 January 2010 to 21 April 2021 about microbiologically confirmed bloodstream infections or meningitis in neonates and AMR in LLMICs were assessed for eligibility. Small case series, studies with a small number of Gram-negative isolates (<10), and studies with a majority of isolates prior to 2010 were excluded. Main outcomes were pooled proportions of Escherichia coli, Klebsiella, Enterobacter, Pseudomonas, Acinetobacter and AMR. We included 88 studies (4 cohort studies, 3 randomised controlled studies, and 81 cross-sectional studies) comprising 10,458 Gram-negative isolates from 19 LLMICs. No studies were identified outside of Africa and Asia. The estimated pooled proportion of neonatal sepsis caused by Gram-negative organisms was 60% (95% CI 55% to 65%). Klebsiella spp. was the most common, with a pooled proportion of 38% of Gram-negative sepsis (95% CI 33% to 43%). Regional differences were observed, with higher proportions of Acinetobacter spp. in Asia and Klebsiella spp. in Africa. Resistance to aminoglycosides and third-generation cephalosporins ranged from 42% to 69% and from 59% to 84%, respectively. Study limitations include significant heterogeneity among included studies, exclusion of upper-middle-income countries, and potential sampling bias, with the majority of studies from tertiary hospital settings, which may overestimate the burden caused by Gram-negative bacteria.

CONCLUSIONS

Gram-negative bacteria are an important cause of neonatal sepsis in LLMICs and are associated with significant rates of resistance to WHO-recommended first- and second-line empirical antibiotics. AMR surveillance should underpin region-specific empirical treatment recommendations. Meanwhile, a significant global commitment to accessible and effective antimicrobials for neonates is required.

Implications of a travel connectivity-based approach for infectious disease transmission risks in Oceania

INTRODUCTION

The increase in international travel brought about by globalisation has enabled the rapid spread of emerging pathogens with epidemic and pandemic potential. While travel connectivity-based assessments may help understand patterns of travel network-mediated epidemics, such approaches are rarely carried out in sufficient detail for Oceania where air travel is the dominant method of transportation between countries.

DESIGN

Travel data from the Australian Bureau of Statistics, Stats NZ and the United Nations World Tourism Organization websites were used to calculate travel volumes in 2018 within Oceania and between Oceania and the rest of the world. The Infectious Disease Vulnerability Index (IDVI) was incorporated into the analysis as an indicator of each country's capacity to contain an outbreak. Travel networks were developed to assess the spread of infectious diseases (1) into and from Oceania, (2) within Oceania and (3) between each of the Pacific Island Countries and Territories (PICTs) and their most connected countries.

RESULTS

Oceania was highly connected to countries in Asia, Europe and North America. Australia, New Zealand and several PICTs were highly connected to the USA and the UK (least vulnerable countries for outbreaks based on the IDVI), and to China (intermediate low vulnerable country). High variability was also observed between the PICTs in the geographical distribution of their international connections. The PICTs with the highest number of international connections were Fiji, French Polynesia, Guam and Papua New Guinea.

CONCLUSION

Travel connectivity assessments may help to accurately stratify the risk of infectious disease importation and outbreaks in countries depending on disease transmission in other parts of the world. This information is essential to track future requirements for scaling up and targeting outbreak surveillance and control strategies in Oceania.