Longitudinal ZOE data stratified by country, time from symptom onset to test, and testing-qualifying symptom era
Time from symptom onset to test was stratified as early (<3 days) versus late (≥3 days). Stratifications show the impact on effect estimates (y-axis) for the three canonical symptoms of anosmia–ageusia, fever, and cough. The x-axis gives the effect estimates when censoring symptoms 0–14 days after the reported COVID-19 test, which might include later-onset symptoms, as well as measurement bias resulting from the knowledge of the test result. ZOE=ZOE COVID Symptom Study app.