P-101. Patient-reported outcomes and home-based self-swabs for influenza-like illness events - Lessons learned from the DANFLU-2 HomeSwab PRO Study
Authors: Soeskov Davidovski Filip , Grundtvig Skaarup Kristoffer , Dyrby Johansen Niklas , Modin Daniel , Shaikh Nabila , Bartelt-Hofer José , Dueger Erica , Loiacono Matthew M , Harris Rebecca C , van Aalst Robertus , Dufournet Marine , Schade Larsen Carsten , Larsen Lykke , Wiese Lothar , Dalager-Pedersen Michael , Jessen Randi , Steenhard Nina , Claggett Brian L , Solomon Scott D , Landray Martin J , Gislaon Gunnar H , Køber Lars , Sivapalan Pradeesh , Stæhr Jensen Jens Ulrik , Jean-Marie Martel Cyril , Biering-Sørensen Tor 
Published: January 2025

Abstract

Background
Patient-reported outcomes (PRO) and self-swab studies may offer to improve monitoring of infectious diseases. The DANFLU-2 HomeSwab PRO study aimed to assess the practicality of self-administered swabs and digital PRO tracking to monitor influenza-like illness (ILI).

Methods
As part of a sub-study of the DANFLU-2 trial, participants were instructed to self-report ILI and quality of life (QoL) using the
Respiratory Intensity and Impact Questionnaire
(RiiQ) for 14 days following symptom onset. If symptomatic, a home-based self-swab was performed, registered via a web app, and mailed to a central center for PCR testing by the participant. Weekly compliance reminders were sent through a governmental electronic letter system.

Results
Overall, 1,976 DANFLU-2 participants were enrolled. During the study period, 208 participants (10.5%) filled out at least one RiiQ, among which 171 (82.2%) reported symptoms fulfilling the ILI case definition. Response rate for completing all 14 days of RiiQs following an ILI event was 85.7% [IQR: 64.3; 100]. In total, 51.4% required phone reminders due to a 48-hour non-response period within the 14 days, with a median of 1 [IQR: 1; 1] contact attempts per non-responding participant. Overall, 89.4% of participants with an ILI event reported having performed a self-swab within a median of 1 day [IQR: 0; 3] from ILI symptom onset. In total, 65.8% of swabs were correctly registered in the web app, and 96.5% of all swabs tested RNaseP positive. During the study, 36 participants (1.8%) withdrew from the study after a median of 59 days [IQR: 25; 108], primarily due to bother from weekly reminders. To reduce dropouts, the possibility of adjusting frequency of reminders was offered, with 40 participants (2.0%) opting to receive monthly reminders and 47 (2.4%) opting to receive no further reminders. The DANFLU-2 staff received 323 e-mails with participant queries about the study. Responses were given to 167 queries via e-mail and 156 via phone calls.

Conclusion
The study confirmed the feasibility of using home-based self-swabs and digital PRO tracking within influenza studies. While the approach proved viable, the findings also highlighted areas for improvement in participant engagement and data collection efficiency.

Disclosures
Kristoffer Grundtvig Skaarup, MD, Sanofi: Board Member Nabila Shaikh, MSc, Sanofi: Stocks/Bonds (Public Company) José Bartelt-Hofer, Dr., Sanofi: Employee|Sanofi: Stocks/Bonds (Private Company) Erica Dueger, Dr., Sanofi: Employee|Sanofi: Stocks/Bonds (Private Company) Matthew M. Loiacono, PhD, MSc, Sanofi: full-time employee|Sanofi: Stocks/Bonds (Public Company) Rebecca C Harris, MBioch, MSc, PhD, Sanofi vaccines: Stocks/Bonds (Private Company) Robertus van Aalst, PhD, MSc, Sanofi: Employee|Sanofi: Stocks/Bonds (Public Company) Marine Dufournet, PhD, Sanofi: Work|Sanofi: Ownership Interest Carsten Schade Larsen, MD, DMSc, Danske Lægers Vaccinations Service: Employee|GSK: Advisor/Consultant|GSK: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Pfizer: Advisor/Consultant|Pfizer: Honoraria|Takeda: Advisor/Consultant|Takeda: Honoraria|Valneva: Advisor/Consultant|Valneva: Honoraria Brian L Claggett, PhD, Amgen: Honoraria|Cardurion: Honoraria|Corvia: Honoraria|Myokardia: Honoraria|Novartis: Honoraria Scott D. Solomon, MD, Actelion: Grant/Research Support|Alnylam: Grant/Research Support|Amgen: Grant/Research Support|AstraZeneca: Grant/Research Support|Bayer: Grant/Research Support|Bellerophon: Grant/Research Support|BMS: Grant/Research Support|Celladon: Grant/Research Support|Cytokintetics: Grant/Research Support|Eidos: Grant/Research Support|Gilead: Grant/Research Support|GSK: Grant/Research Support|Ionis: Grant/Research Support|Lilly: Grant/Research Support|Mesoblast: Grant/Research Support|Myokardia: Grant/Research Support|Neurotronik: Grant/Research Support|NIH/NHLBI: Grant/Research Support|Novartis: Grant/Research Support|Novartis: Honoraria|Novo Nordisk: Grant/Research Support|Sanofi: Grant/Research Support|Theracos: Grant/Research Support|US2.AI: Grant/Research Support Lars Køber, MD, DMSc, AstraZeneca: Honoraria|Bayer: Honoraria|Boejringer Ingelheim: Honoraria|Novartis: Honoraria|Novo Nordisk: Honoraria Tor Biering-Sørensen, MD, PhD, Amgen: Advisor/Consultant|Bayer: Honoraria|Boston Scientific: Honoraria|CSL Squirus: Honoraria|GE Healthcare: Honoraria|GSK: Honoraria|Novartis: Honoraria|Novo Nordisk: Honoraria|Sanofi: Honoraria