Quantifying additional COVID-19 symptoms will save lives

Public health authorities across the world have been trying to contain the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via public awareness and contact tracing—ie, by identifying and isolating individuals at high risk of being positive.1 In many countries, regular mass swab testing is still inadequate. Using self-reported symptoms data from 18 401 users of the COVID Symptom Study app, who underwent an official SARS-CoV-2 test (7104 testing positive, 11 297 testing negative), we previously reported that loss of smell and taste is a potential predictor of COVID-19 in addition to the most established symptoms of a high temperature and a new, continuous cough.2 The prevalence of loss of smell and taste was three-fold higher in individuals testing positive (65·03%) than in those testing negative (21·71%),2 suggesting that people with loss of smell and taste should self-isolate. CM declares funding through a National Institute for Health Research Clinical Doctoral Research Fellowship.