Symptom reporting in over 1 million people: community detection of COVID-19

Abstract

Control of the SARS-CoV-2 epidemic requires rapid identification and isolation of infected individuals and their contacts. Community testing in England (Pillar 2) by polymerase chain reaction (PCR) is reserved for those reporting at least one of four 9classic9 COVID-19 symptoms (loss or change of sense of smell, loss or change of sense of taste, fever, new continuous cough).1 Detection of positive cases in the community might be improved by including additional symptoms and their combinations. We used data from the REal-time Assessment of Community Transmission-1 (REACT-1) study to investigate symptom profiles for PCR positivity at different ages. Among rounds 2-7 (June to December 2020), an age-stratified, variable selection approach stably selected chills (all ages), headache (5-17 years), appetite loss (18-54 and 55+ years) and muscle aches (18-54 years) as jointly and positively predictive of PCR positivity together with the classic four symptoms. Between round 7 (November to December 2020) and round 8 (January 2021) when new variant B.1.1.7 predominated, only loss or change of sense of smell (more predictive in round 7) and (borderline) new persistent cough (more predictive in round 8) differed between cases. At any level of PCR testing, triage based on the symptoms identified here would result in more cases detected than the current approach.