Predictors of Paediatric Influenza-like-Illness Severity During the COVID-19 Pandemic*George James Porter1 and Stephen Owens2,3Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom.Department of Paediatric Immunology and Infectious Diseases, Great North Children’s Hospital, Newcastle upon Tyne Hospital NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.Population Health Sciences Institute, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom.*Indicates the corresponding author, correspondence to: firstname.lastname@example.orgWord Count: 807Respiratory viral illness is a common cause of paediatric admission in the UK. It is estimated that In an average winter in the UK, 2.4% of children under five will have a respiratory illness attributable to Influenza A alone.(1) Despite the importance of viral respiratory infection, the predictive value of symptoms, co-morbidities and viral isolation are debated.(2) For example, in an American study of 241 children presenting to hospital with influenza-like-illness (ILI) the risk of severe complications was only increased by neurological/neuromuscular disease.(3) Meanwhile, a similar British study analysing 265 paediatric H1N1-positive ILI patients each with 2 virus-negative ILI controls found that chronic lung disease, cerebral palsy, chest retractions, tachycardia, dehydration and oxygen requirement predicted adverse outcome across the two groups.(4)The ongoing COVID-19 pandemic has shown that surges of acute respiratory infections must be planned for by the health service. Therefore, clearer definition of the early indicators of high-risk patients could be of considerable benefit regarding resource allocation and risk stratification. Equally, few studies have taken into account demographic data (including age and ethnicity), co-morbidities and symptoms and signs at presentation simultaneously.(5) We therefore conducted a retrospective study to help identify the predictors of severity of ILI in the North East of England during the height of the coronavirus pandemic.We defined ILI as the presence of fever ≥37.8oC and one other upper respiratory symptom. A cohort of children hospitalised with ILI in Newcastle-Upon-Tyne hospitals between 01/03/2020 and 05/05/2020 was identified from trust records. Information on symptoms at presentation, past medical history, demographics and outcomes was extracted. Disease severity was approximated by admission length, oxygen usage and intensive care unit (ITU) admission. Regression modelling identified variables which impacted these outcomes.