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Introduction Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes encephalitis and other morbidity in Southeast Asia. Since February 2022, geographically dispersed JEV human, animal and vector detections occurred on the Australian mainland for the first time. This study will determine the prevalence of JEV-specific antibodies in human blood with a focus on populations at high risk of JEV exposure and determine risk factors associated with JEV seropositivity by location, age, occupation and other factors.Method Samples are collected using two approaches: from routine blood donors (4153 samples), and active collections targeting high-risk populations (convenience sampling). Consent-based sampling for the latter includes a participant questionnaire on demographic, vaccination and exposure data. Samples are tested for JEV-specific total antibody using a defined epitope-blocking ELISA, and total antibody to Australian endemic flaviviruses Murray Valley encephalitis and Kunjin viruses.Analysis Two analytic approaches will occur: descriptive estimates of seroprevalence and multivariable logistic regression using Bayesian hierarchical models. Descriptive analyses will include unadjusted analysis of raw data with exclusions for JEV-endemic country of birth, travel to JEV-endemic countries, prior JEV-vaccination, and sex-standardised and age-standardised analyses. Multivariable logistic regression will determine which risk factors are associated with JEV seropositivity likely due to recent transmission within Australia and the relative contribution of each factor when accounting for effects within the model.Ethics National Mutual Acceptance ethical approval was obtained from the Sydney Children’s Hospitals Network Human Research Ethics Committee (HREC). Local approvals were planned to be sought in each jurisdiction, as per local ethics processes. Ethical approval was also obtained from the Australian Red Cross Lifeblood HREC.Dissemination Findings will be communicated to participants and their communities, and human and animal health stakeholders and policy-makers iteratively and after final analyses. Understanding human infection rates will inform procurement and targeted allocation of limited JEV vaccine, and public health strategies and communication campaigns, to at-risk populations.

Abstract Background From a Public Health Unit (PHU) perspective, this review aimed to examine factors associated with adverse outbreak outcomes, to identify evidence based focal strategies of managing COVID-19 outbreaks in aged care settings. Methods A retrospective review of PHU documentation examined all 55 COVID-19 outbreaks in Wide Bay RACFs across the first 3 COVID-19 waves in Queensland, through thematic and statistical analysis. ​. Results Thematic analysis using the framework approach identified 5 themes associated with outcomes of COVID-19 outbreaks in RACFs. These were analysed for statistical significance against outbreak outcomes including duration, attack rate and case fatality rate. There was a significant relationship between memory support unit (MSU) involvement and adverse outbreak outcomes. Attack rate was significantly associated with communication frequency, symptom monitoring and case detection approach, staff shortages and cohorting. Staff shortages were also significantly associated with a prolonged outbreak duration. There was no statistically significant relationship between outbreak outcomes and resource availability or infection control strategy. ​. Conclusions This emphasises the importance of frequent communication between PHUs and RACFs during active outbreaks, as well as the need for regular symptom monitoring and prompt case detection, to minimise viral transmission. Staff shortages and cohorting are also crucial factors to be addressed during outbreak management. Implications for Public Health This review adds to the evidence basis of COVID-19 outbreak management strategies to improve PHU advice to RACFs, to mitigate viral transmission and ultimately reduce the burden of disease associated with COVID-19 and other communicable diseases.