Patient-reported outcomes and home-based self-swabs for influenza-like illness events - lessons learned from the 2023/2024 DANFLU-2 Homeswab PRO substudy
Year: 2025
Type: article
Abstract: BACKGROUND: Self-swabs and digital patient-reported outcomes (PROs) offer innovative tools for decentralized monitoring of infectious diseases. The DANFLU-2 HomeSwab PRO substudy evaluated the feasibility of using these methods for tracking influenza-like illness (ILI) within a large-scale, pragmatic, randomized trial. METHODS: During the 2023/2024 influenza season, adults aged ≥ 65 years were recruited from the DANFLU-2 trial, which evaluates the relative effectiveness of high-dose influenza vaccine compared to standard-dose. Participants were instructed to self-swab at home upon ILI symptom onset and complete the Respiratory Infection Intensity and Impact Questionnaire (RiiQ™) for 14 days. Swabs were registered via QR code in a webapp and mailed for centralized PCR testing. Compliance was defined as completing all 14 days of RiiQ™ reporting. RESULTS: Among 1,976 enrolled participants, 208 (10.5%) completed at least one RiiQ™, and 171 (82.2%) met the ILI case definition. Most participants found self-swabbing easy (66.1%) and more practical than visiting a clinic (78.6%). Compliance with daily RiiQ™ symptom tracking was 85.7%. Among those with ILI, 89.4% performed a self-swab within 1 day [IQR: 0; 3] of symptom onset; 65.8% of swabs were correctly registered in the webapp, and 96.5% were RNaseP-positive. Thirty-six participants (1.8%) withdrew, mainly due to weekly reminders; allowing reduced reminder frequency improved retention. CONCLUSION: The study confirmed the feasibility of using home-based self-swabs for remote disease diagnosis and digital PRO tracking for symptoms during ILI events in a large-scale, pragmatic randomized trial. While the approach proved viable, the findings also highlighted areas for improvement in participant engagement and data collection efficiency. GOV ID: NCT05517174.
Authors: Filip Soeskov Davidovski, Kristoffer Grundtvig Skaarup, Niklas Dyrby Johansen, Daniel Modin, Nabila Shaikh, Jose Bartelt-Hofer, Matthew M. Loiacono, Rebecca C. Harris, Carsten Schade Larsen, Lykke Larsen, Lothar Wiese, Michael Dalager-Pedersen, Randi Jessen, Nina Steenhard, Brian L. Claggett, Scott D. Solomon, Lars Køber, Pradeesh Sivapalan, Jens Ulrik Staehr Jensen, Cyril Jean-Marie Martel, Tor Biering-Sørensen
Institutions: University of Copenhagen, Herlev Hospital, Copenhagen University Hospital, Gentofte Hospital, Sanofi (United Kingdom), Sanofi (France), Sanofi (United States), Aarhus University Hospital, Odense University Hospital, Roskilde Sygehus, Zealand University Hospital, Aalborg University Hospital, Statens Serum Institut, Brigham and Women's Hospital, Harvard University, Rigshospitalet, Steno Diabetes Center Copenhagen
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,990
OpenAlex ID: W4413430935