Background We developed a self-assessment and participatory surveillance web application for coronavirus disease (COVID-19), which was launched in France in March 2020. Objective Our objective was to determine if self-reported symptoms could help monitor the dynamics of the COVID-19 outbreak in France. Methods Users were asked questions about underlying conditions, sociodemographic status, zip code, and COVID-19 symptoms. Depending on the symptoms reported and the presence of coexisting disorders, users were told to either stay at home, contact a general practitioner (GP), or call an emergency phone number. Data regarding COVID-19–related hospitalizations were retrieved from the Ministry of Health. Results As of March 29, 2020, the application was opened 4,126,789 times; 3,799,535 electronic questionnaires were filled out; and 2,477,174 users had at least one symptom. In total, 34.8% (n=1,322,361) reported no symptoms. The remaining users were directed to self-monitoring (n=858,878, 22.6%), GP visit or teleconsultation (n=1,033,922, 27.2%), or an emergency phone call (n=584,374, 15.4%). Emergency warning signs were reported by 39.1% of participants with anosmia, a loss of the sense of smell (n=127,586) versus 22.7% of participants without anosmia (n=1,597,289). Anosmia and fever and/or cough were correlated with hospitalizations for COVID-19 (Spearman correlation coefficients=0.87 and 0.82, respectively; P <.001 for both). Conclusions This study suggests that anosmia may be strongly associated with COVID-19 and its severity. Despite a lack of medical assessment and virological confirmation, self-checking application data could be a relevant tool to monitor outbreak trends. Trial Registration ClinicalTrials.gov NCT04331171; https://clinicaltrials.gov/ct2/show/NCT04331171
【저자키워드】 COVID-19, Epidemiology, Symptoms, Anosmia, Surveillance, outbreak, epidemiological surveillance, web application, self-assessment, 【초록키워드】 coronavirus disease, Hospitalization, severity, Symptom, cough, Registration, COVID-19 outbreak, Fever, France, correlation, underlying conditions, COVID-19 symptoms, questionnaire, Emergency, Contact, sense of smell, no symptoms, user, Virological, disorders, help, participant, Sociodemographic, MONITOR, Spearman, Ministry of Health, objective, self-reported symptom, Result, lack, reported, determine, question, correlated, asked, retrieved, with COVID-19, 【제목키워드】 application, observation, Web,