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J Patient Rep Outcomes
. 2025 Aug 22;9(1):108.
doi: 10.1186/s41687-025-00936-8. Patient-reported outcomes and home-based self-swabs for influenza-like illness events - lessons learned from the 2023/2024 DANFLU-2 Homeswab PRO substudy
Filip Soeskov Davidovski 1 2 , Kristoffer Grundtvig Skaarup 3 4 , Niklas Dyrby Johansen 3 4 , Daniel Modin 3 4 , Nabila Shaikh 5 , Jose Bartelt-Hofer 6 , Matthew M Loiacono 7 , Rebecca C Harris 8 , Carsten Schade Larsen 9 , Lykke Larsen 10 , Lothar Wiese 11 , Michael Dalager-Pedersen 12 13 , Randi Jessen 14 , Nina Steenhard 14 , Brian L Claggett 15 , Scott D Solomon 15 , Lars Køber 16 17 , Pradeesh Sivapalan 16 18 , Jens Ulrik Staehr Jensen 16 18 , Cyril Jean-Marie Martel 14 , Tor Biering-Sørensen 19 20 21 22
Affiliations
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.
Keywords: Compliance; DANFLU-2 trial; Digital patient-reported outcomes (PRO); Feasibility study; Home-based testing; Influenza-like illness (ILI); Respiratory intensity and impact questionnaire (RiiQ); Self-swabs.
. 2025 Aug 22;9(1):108.
doi: 10.1186/s41687-025-00936-8. Patient-reported outcomes and home-based self-swabs for influenza-like illness events - lessons learned from the 2023/2024 DANFLU-2 Homeswab PRO substudy
Filip Soeskov Davidovski 1 2 , Kristoffer Grundtvig Skaarup 3 4 , Niklas Dyrby Johansen 3 4 , Daniel Modin 3 4 , Nabila Shaikh 5 , Jose Bartelt-Hofer 6 , Matthew M Loiacono 7 , Rebecca C Harris 8 , Carsten Schade Larsen 9 , Lykke Larsen 10 , Lothar Wiese 11 , Michael Dalager-Pedersen 12 13 , Randi Jessen 14 , Nina Steenhard 14 , Brian L Claggett 15 , Scott D Solomon 15 , Lars Køber 16 17 , Pradeesh Sivapalan 16 18 , Jens Ulrik Staehr Jensen 16 18 , Cyril Jean-Marie Martel 14 , Tor Biering-Sørensen 19 20 21 22
Affiliations
- PMID: 40844659
- DOI: 10.1186/s41687-025-00936-8
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.
Keywords: Compliance; DANFLU-2 trial; Digital patient-reported outcomes (PRO); Feasibility study; Home-based testing; Influenza-like illness (ILI); Respiratory intensity and impact questionnaire (RiiQ); Self-swabs.