DETECTION of SARS-CoV-2 infection through PCR eligibility triad symptoms of cough, fever, and loss of smell has been deemed ineffective by a group of researchers at King’s College London, London, UK following an advanced study using the COVID Symptom Study app designed by the university, ZOE. The researchers advised that if the triad symptoms were extended to include fatigue, sore throat, headaches, and diarrhoea, the first 3 days of illness would have detected 96% of symptomatic cases. Although the PCR swab testing is currently the most authentic way of exposing a SARS-CoV-2 infection, this study stated that by using the limited symptoms list, almost one-third of coronavirus disease (COVID-19) cases are missed by the UK’s National Health Service (NHS).
The researchers at King’s College London worked alongside the Coalition for Epidemic Preparedness Innovations (CEPI) and examined data of more than 122,000 UK adult participants who used ZOE. The app recorded symptoms from the users and the researchers compared these results with those of 1,202 participants who received a positive PCR test within the first week of feeling unwell. Information obtained from the ZOE app indicated that 31% of people with COVID-19 do not display triad of symptoms in the onset stages of the disease when its most infectious.
A multi-objective evolutionary algorithm depending on the testing capacity was used to produce optimal symptom combinations. These symptoms combinations were characterised by specificity and sensitivity. Results showed that cough or dyspnoea (shortness of breath) were reported by 46% of individuals testing positive for COVID-19 during the first 3 days of onset of symptoms. With the fever, the sensitivity had risen to 60%, and with the added symptom of anosmia/ageusia increased sensitivity to 69% was recorded. Finally, for the fatigue and headache symptom the proportion of COVID-19 case sensitivity was 92%.
Dr Jakob Cramer, Head of Clinical Development, at CEPI, said: ” The findings of this study provide important insights that will help optimise the choice of triggering symptoms for diagnostic work-up in COVID-19 vaccine-efficacy trials. We hope the findings of this study will not only aid CEPI’s COVID-19 vaccine-development partners but also the wider research and development community.”