675 Symptoms of SARS-CoV-2 infection in the UK paediatric population

Background During the first wave of the pandemic in 2020, Covid-19 symptoms of cough, fever and loss of taste/smell were identified in the adult population and aided diagnostic PCR testing. However, children with similar symptoms appeared less likely to test positive or to develop severe disease. As part of a multi-centre observational cohort study from 16th April 2020 to 3rd July 2020, 992 paediatric participants aged 2-15 years, were recruited and underwent SARSCoV- 2 antibody testing and provided symptom data. Objectives To identify the proportion of healthy children who demonstrated antibody response to SARS-CoV-2 infection in this cohort of healthcare worker's children. To identify the symptoms experienced by participants who had the presence of SARS-CoV-2 antibodies. To assess if there was correlation between different symptoms experienced and SARS-CoV-2 antibody titres in a paediatric population. Methods 1007 participants were enrolled and 992 were included in the final analysis. Participants were identified across 5 UK sites-Belfast, Glasgow, Cardiff, Manchester and London. All participants were healthy children of NHS healthcare workers. Participants underwent phlebotomy and provided blood samples for SARS-CoV-2 antibody testing and information on their symptoms in the form of an electronic case report form (CRF). Serum and/or plasma was tested for antibodies to SARS-CoV-2 using nucleocapsid and spike protein assays. Study data was recorded on a CRF using REDCap and information recorded included age, sex, previous health, recent symptoms and potential predictors of presence of SARs-CoV-2 antibodies including contact with confirmed or suspected cases. Results Of the 992 patients included, 962/992 (97%) had complete CRFs. The median age of study participants was 10.1 years (2.03-15.99yrs) and 51% were male. There were 68/992 participants with positive SARS-CoV-2 antibodies, giving a seroprevalence of 6.9%. Of those with positive SARSCoV- 2 antibody tests, 34/68 (50%) were asymptomatic. In the symptomatic participants (34/68), the most commonly reported symptoms were fever 21/68 (31%), gastrointestinal symptoms 13/68 (19%) and headache 12/68 (18%). The presence of fever, cough or change in smell/taste was reported by 26/68 (38%) of antibody positive participants. None of the participants experienced severe symptoms requiring hospital admission. One of the assays (Abbott Architect SARS-CoV-2 IgG assay), indicated a small but significant increase in mean antibody titres between asymptomatic 4.3 S/C (95% CI 3.4 to 5.2) and symptomatic participants 5.5 S/C (95% CI 4.7 to 6.2), but this was not replicated with Roche Elecsys or DiaSorin LIAISON assays which found no significant difference. Conclusions Following the first wave of the pandemic, 68/992 (6.9%) of children of healthcare workers in UK had evidence of previous SARS-CoV-2 infection. Importantly, only 50% of these children experienced symptoms and this highlights the potential for asymptomatic children to be missed by current NHS testing guidelines. The symptoms which adults often experience, namely pyrexia, cough and loss of taste/smell, were only experienced by 38% of children who had SARSCoV- 2 antibodies. These children were more likely to experience gastrointestinal symptoms or lethargy and headache and therefore raises the question of whether this should be factored into current symptomatic testing guidelines.