Prevalence of SARS-CoV-2 antibodies in asymptomatic children with unexplained symptoms

Abstract

Background and aim. Since COVID pandemics, ~50% of children can have asymptomatic infection. However, they tend to have post-covid symptoms. Due to unexplained symptom origin (without confirmed COVID), they are referred to different paediatric specialists. Aims:to analyse SARS-CoV-2 antibody levels in children referred to our University Hospital ambulatory care with unexplained symptoms, to clarify percentage of asymptomatic covid cases and related post-covid symptoms. Methods:prospective study was conducted including children up to age of 18y without previous SARS-CoV-2 infection, were not breastfed during the last months, nor vaccinated against SARS-CoV-2. Parents were asked to fill-in the questionnaire about symptoms within one year before referral. Results:in total, 124 children were included into the study, 47.5% were female. Median age was 8.6y. 63.7% had different chronic diseases, e.g., asthma or arthritis and 56.4% were allergic. 41% noted that they have had symptoms of acute infection within one year, 24% had family member who tested positive for SARS-COV-2. 24.2% of children had antibodies against SARS-CoV-2 (Ab+). No correlation between positive test of family member and Ab+ child was found. No significant difference was observed between Ab+ versus Ab- within age groups, with or without chronic diseases. There were 57 children with unexplained symptoms and 26% of those children had Ab+. Most of those symptoms were respiratory (dyspnoea, cough), followed by neurological symptoms (insomnia, tiredness). Conclusions:we did find 24% of the Ab+ children who were defined as never ill with COVID. Majority of unexplained symptoms within the Ab+ group were respiratory and/or neurological.