Application scoping and conceptual design occupied a significant portion (8 months) of our project timeline due to the need to ensure that we had the appropriate type and level of functional capability included in the application. A variety of different stakeholder consultation sessions were held with RACF and PHU staff to understand design needs (see Table 1, item 6), and through the establishment and use of a working group, we were able to finalize and agree on a minimum viable product (MVP; see Figure 1).

Through the RACF stakeholder consultation sessions (see Figure 1), the PHU identified 3 key barriers to effective influenza surveillance and outbreak response and, with the working group, designed a series of features that addressed these barriers, as shown in Table 2 below. The working group membership included clinical and epidemiological staff from within the PHU, geriatric care managers and senior information and communication technology (ICT) staff from across the district, and managers of respiratory diseases from within Health Protection NSW. The group met weekly to advise on the components or features of the application and together produced a comprehensive business requirements document from which only the essential elements for an initial MVP build had to be identified and agreed on (see Figure 1).

Once the MVP was developed, a comprehensive audit of the application’s content, algorithm, and functions was conducted, as well as external user acceptability testing (UAT) with a focus group of self-volunteered RACF staff (see Figure 1). The UAT was designed as a guided, hands-on training session on FluCARE followed by a structured feedback session with comments obtained via moderated group discussion. This testing identified minor issues and potential improvements, such as changes to interface workflow. The MVP then underwent further cycles of testing and enhancement prior to pilot launch. After the MVP launch, an independent security assessment verified that the technical and architectural design of the application met governing standards (Table 1, item 15 and Figure 1). Further to this audit and to support appropriate local procedures in how FluCARE data were managed, the PHU underwent an internal security risk assessment and developed a risk management plan with our IT services prior to launch. This was particularly important as the application transitioned from the digital developer’s environment to being hosted by the SLHD ICT local servers (see Figure 1).

Even after launch, the FluCARE application underwent further refinements over time in accordance with PHU or RACF feedback. The most significant enhancement was a rapid 6-week development in March 2020 to incorporate COVID-19 monitoring and outbreak detection (see Figure 1). At the time of developing the FluCARE application, there was no standardized and validated way to report the features of a web-based application, so the features of FluCARE have been described as per the World Health Organization checklist on Mobile Health Evidence Reporting and Assessment criteria above (see Multimedia Appendix 1 [10]).

User-centric design is a well-understood principle in IT projects [3,5,18-20]. From the outset, we were mindful that FluCARE’s capacity to improve outbreak outcomes was dependent on its ability to be accepted and adopted by RACF staff. This is typically determined by factors such as an application’s perceived usefulness, reliability, and user-friendliness [5,21]. As such, input from RACF staff was pivotal. Beyond informing the core functions of the application, feedback from RACF staff via the various user engagement and testing episodes embedded in our design and development process (see Figure 1; 0-27 months) was valuable in answering key design questions encountered by the working group and digital developers, for example, whether to optimize the application for desktop versus mobile use. Lastly, while acknowledging the importance of user-based design in the development of a digital health tool, no one design approach is accepted as a gold standard [22]. However, we did not conduct our user-based design activity through a theoretical framework or research process and would have benefited from such a systematic approach.

Data security and information privacy is a central concern that must be thoroughly addressed to ensure user acceptability, and that ethical and professional obligations are met, particularly when dealing with personally identifiable health data [5,23]. Addressing all facets of security appropriately required not only an understanding of the legislation, policies, and procedures in place to secure and manage health data appropriately within New South Wales but also a practical risk management approach in order to mitigate any perceived risks to data breaches. Based on the recommendations from the independent security assessment, the working group developed a user access management policy and security risk management plan to help mitigate any inappropriate access or use of the application and to ensure the security of the personal health information within the application (Figure 1; 15‐27 months). While much of the existing literature focuses on the technical aspects of security, it is important to recognize that data governance strategies, staff training, and incident detection and response plans are also essential for security [24-26]. This multifaceted security approach was applied for FluCARE, as detailed in Table 1 (item 14).

Supportive organizational culture and structures for digital health innovation are important enablers for successful design and implementation [5,27]. FluCARE development was undertaken within a forward-thinking organization where innovation in health care IT is a strategic priority [28]. The project received high-level support at initiation through the SLHD executive as well as at the PHU and IT departmental levels, which facilitated supportive resourcing from the IT department, including their de novo build of the required hosting environment for FluCARE. However, we may have potentially benefited from an organization-wide mechanism for pooling institutional experience and sharing resources across different projects, given that a number of other application developments were also occurring in the SLHD over the time period of the design, development, and implementation of FluCARE (see Figure 1). This has potential for leveraging economies of scale, reducing duplicative overhead costs, optimizing interoperability, and improving procedural efficiencies [5,29].