COVID-19 pediátrico: perfil epidemiológico, sintomático e performance de testes diagnósticos

Abstract

With the first cases of SARS-CoV-2 infection in December 2019 and its global spread, the scientific community quickly mobilized to research and produce studies aimed at understanding this previously unknown disease. Initially, the majority of those affected were adults, and academic efforts were directed towards this age group. However, as the pandemic progressed, an increase in paediatric COVID-19 cases was observed, including severe outcomes, with a rising trend in the percentage of Severe Acute Respiratory Syndrome (SARS) due to COVID-19 in children in Brazil. Despite this, studies on clinical presentation, outcomes, and diagnostic test performance in this population are still scarce. In this context, this study aims to describe the clinical manifestations of COVID-19 in individuals under 18 years of age, comparing them to the adult population, and to assess the performance of rapid antigen tests in diagnosing COVID-19 in this age group. This is a prospective observational cohort study conducted at the Centro de Triagem e Diagnóstico de COVID-19 at the Universidade Federal do Rio de Janeiro (CTD-UFRJ), analysing samples collected from August 2020 to November 2023. The cohort included 1,063 patients aged 0 to 18 years, representing 3.1% of the total number of individuals tested. Among children, the most prevalent symptoms were cough, runny nose, sneezing, and nasal congestion. Unlike adults, there was no association between COVID-19 diagnosis and the presence of cough, ageusia, chills, myalgia, or asthenia. However, in this age group, there was a positive association between headache and conjunctival congestion with a positive result, which was not seen in adults. Symptom distribution varied when comparing different paediatric age groups. Headache was positively associated with a COVID-19 diagnosis in those aged 6 to 12 years, while in those aged 13 to 18 years, fever and anosmia were positively associated, resembling the adult population. In the 0 to 5-year age group, no symptoms were positively associated with a COVID-19 diagnosis, and cough, nasal congestion, nausea, and vomiting were negatively associated. Regarding the comparison of viral load in respiratory samples, individuals under 18 had significantly lower values than adults, particularly those under 5 years of age. This lower viral load might correlate with poorer performance of antigen tests, as reported in the literature. However, it should be noted that test performance is associated with the type of sample collected, and no difference was found between adults and children when only nasal swabs were compared. In conclusion, clinical presentation in individuals under 18 differs from that in adults. Additionally, it varies within the paediatric population across different age groups, and symptoms, in general, have low predictive value for diagnosing COVID-19 in this population. Finally, the lower viral load detected in respiratory samples appears to be associated with the type of collection method (nasal vs nasopharyngeal) rather than the specific population.