Evaluation of a Japanese encephalitis vaccine decision aid in adults travelling overseas to at-risk areas

Intervention being studied: The intervention is an online Japanese Encephalitis Vaccine Decision Aid (JEVADA), developed according to the International Patient Decision Aids Standards (IPDAS) and created using a comprehensive co-design and user-testing process (described below). JEVADA takes users through a self-guided, step-by-step process, divided into three key sections, along with additional resources such as a Frequently Asked Questions (FAQ) page. It provides detailed information on Japanese encephalitis, including its geographic distribution, transmission methods, clinical features, severity, and associated risks. Preventive measures, including mosquito bite avoidance strategies and a comparison of the available vaccines in Australia, are also covered. JEVADA encourages participants to reflect on their personal circumstances, values, and beliefs to help guide their vaccination decision, while prompting them to consult with a healthcare provider to discuss their options. The tool includes visual aids and interactive elements to support decision-making, such as a side-by-side risk-benefit analysis and a values clarification exercise. JEVADA is designed as an educational resource, and emphasises the importance of consulting a trusted healthcare provider before making a vaccination decision. A downloadable short-form PDF version of the decision aid, offering a condensed version of the content (without interactive features), is also available. Mode of delivery: Online. Procedures: Participants assigned to the intervention arm will receive a link to JEVADA and will be asked to review the materials. Timing: The intervention will be delivered in a single session, during which participants will also complete pre- and post-intervention surveys. The estimated time to review JEVADA is approximately 15 minutes. Location: Participants can access JEVADA from any location of their choice. Strategies to monitor adherence: Participants will complete self-reported questions regarding the extent of their review, including time spent and whether they reviewed the entire content or only specific sections. Additionally, we will track the time elapsed between the completion of pre- and post-intervention surveys. Website analytics will also be used to capture the timing, frequency, and duration of visits to the decision aid website during the intervention period. JEVADA co-design and user testing process: The co-design process involved Australian consumers and healthcare providers. Three rounds of Zoom workshops, each lasting two hours, were held over five months. The first two rounds focused on decisional needs and design requirements, with separate sessions for consumers and providers. Participants reviewed example components and gave feedback. In the final round, both groups were brought together to evaluate a prototype of the decision aid, commenting on its language, layout, and presentation. Feedback was collected verbally, via chat, and through an online whiteboard. Those who missed the final session provided feedback by email. User testing involved semi-structured Zoom interviews with a new group of consumers and providers. A "think aloud" method was used to explore their interactions with the prototype. Additional feedback was collected through a follow-up survey. Content experts in vaccination, vector-borne diseases, encephalitis, and travel medicine also reviewed the decision aid and provided feedback via an online survey. A steering group of experts in immunisation, travel medicine, vaccine communication, social science, and a consumer representative oversaw the process. They worked with a graphic designer to create iterative PDF prototypes informed by co-design and user testing, which were later adapted into a web-based format by a developer.