Gripenet 2025/26: re-establishing participatory surveillance in Portugal

Background

Gripenet is Portugal’s participatory surveillance platform for respiratory symptoms (RS), integrated into the Influenzanet network. It was relaunched in the 2025/26 season to complement traditional sentinel surveillance and expand real-time, population-based monitoring of RS. This presentation describes the operational set-up, participant engagement strategies and lessons learned from re-establishing participatory surveillance in Portugal.

Methods

Sociodemographic data, weekly RS, healthcare-seeking behaviour and vaccination status are collected. Parents or guardians may report on behalf of minors. Participants were recruited via social media, partner networks and contact with previous participants from week 50/2025. Operational monitoring covered platform performance, registration trends, response rates and data completeness. Participant dashboards became available mid-season. Response patterns were analysed by engagement profile and RS notification peaks were examined.

Results

As of week 17/2026, a total of 605 participants had registered in the platform. The majority were female (51.6%), with a median age of 53 years. Most participants held higher education qualifications (82.0%), and the geographic distribution was skewed towards metropolitan areas. Weekly response rates averaged 55.5%. Three engagement profiles were identified: consistent responders (36.7%), occasional responders (53.9%) and participants who never submitted after registration (9.4%). RS notification peaks were observed in week 52/2025 (15.0%), being relatively stable for the rest of the weeks.

Conclusions

While 605 participants represent an encouraging start, future efforts will prioritise sustained engagement and retention through citizen science approaches and reward mechanisms. The delayed availability of results dashboards may have hindered motivation. This experience provides a solid foundation for strengthening Gripenet in future seasons.

Key messages

• Gripenet was successfully relaunched as a participatory system for respiratory symptom surveillance, showing operational viability and potential to complement sentinel surveillance in Portugal.

• Results indicate the importance of continuous engagement and retention strategies, including timely feedback and citizen science approaches to ensure the systems sustainability.