BMJ Open (Feb 2024)

Seroprevalence of Japanese encephalitis virus-specific antibodies in Australia following novel epidemic spread: protocol for a national cross-sectional study

  • ,
  • Keira Glasgow,
  • Kirsty Hope,
  • Deborah Williamson,
  • Tom Snelling,
  • Angela Ratsch,
  • Vicki Krause,
  • Gulam Khandaker,
  • Kristine Macartney,
  • Dominic E Dwyer,
  • Nicola Spurrier,
  • David O Irving,
  • Jannah Baker,
  • Helen O’Brien,
  • Paul Worley,
  • Louise Flood,
  • Jacina Walker,
  • Nicolas Smoll,
  • Stephen Lambert,
  • Jane Nelson,
  • Noni Ella Winkler,
  • Archana Koirala,
  • Guddu Kaur,
  • Shayal Prasad,
  • Rena Hirani,
  • Veronica Hoad,
  • Iain B Gosbell,
  • Linda Hueston,
  • Matthew VN O'Sullivan,
  • Jen Kok,
  • Chloe Luscombe,
  • Adriana Notaras,
  • Zoe Baldwin,
  • Jennifer Case,
  • Tilda Thomson,
  • Madeleine Marsland,
  • N Deborah Friedman,
  • Heidi Carroll,
  • Candice Holland,
  • Scott Kitchener,
  • Josette Chor,
  • Alice Sykes,
  • Liam Flynn,
  • Aleena Williams,
  • Alexandra Hinchcliff,
  • Bart Currie,
  • Rebecca Beazley,
  • Carmen Hayward

DOI
https://doi.org/10.1136/bmjopen-2023-075569
Journal volume & issue
Vol. 14, no. 2

Abstract

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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.