FluStudy2020 Design
sore throat, fever, fatigue, cough, ache, nasal congestion, headache, chills
SORE THROAT, INFLUENZA
Participants were enrolled in the FluStudy2020 study if they were aged ≥18 years, lived in the United States, and wore a Fitbit device with heart rate (HR)-tracking capabilities. Participants were excluded from the study if they had been diagnosed with influenza by a health care professional in the previous 3 months.Before enrollment, the participants completed a baseline survey, which collected data regarding key demographics, medical history, comorbidities, and influenza history (specifically, prior influenza diagnosis, previous influenza treatment, and current influenza vaccination status).The participants completed daily surveys for the first 120 days and fortnightly surveys for the remainder of the study period. If the participants reported ILI symptoms within the previous 24 hours, detailed symptom, quality of life (QoL), and health care use data were collected through follow-up surveys. To verify the diagnoses, an influenza diagnostic kit (self-administered nasal swab [Molecular Testing Labs]) was sent to the participants who experienced fever, at least 1 respiratory symptom (cough, sore throat, or nasal congestion), and at least 1 systemic symptom (headache, muscle or joint ache, chills, or fatigue). The diagnostic criteria were based on those highlighted by precedents in the literature and influenza clinical trials [