BACKGROUND: Current surveillance of travellers' health captures only a small proportion of illness events. We aimed to evaluate the usability and feasibility of using an app to enable travellers to self-report illness. METHOD: This pilot study assesses a novel mobile application called Infection Tracking in Travellers (ITIT) that records travel-related symptoms with associated geolocation and weather data. Participants were recruited in three Swiss travel clinics between December 2021 and March 2022. A feedback survey was used to examine app ease of use, and data from the app was used to examine travel and illness patterns as a proof-of-concept for the larger ITIT study. RESULTS: Participants were recruited from Zurich, Basel, and Geneva, with 37 individuals completing a total of 394 questionnaires in 116 locations in Asia, Africa, the Americas, and Europe. Illness symptoms were reported by 41% of participants, 67% of which were respiratory. The post travel questionnaire showed that all participants found the app easy to use and 63% said they would recommend it to others. Several users provided suggestions for improved usability. CONCLUSION: The app fulfilled its function as a research tool linking infection symptoms with geolocation and climate data
