A retrospective study was conducted on a database of the COVID-19 Tracking Program in schoolchildren to identify the prevalence of COVID-19 through serology and RT-PCR in children, adolescents, and adults.
The data was composed of sociodemographic and clinical variables, results of serological tests (IgM and IgG), and RT-PCR results of IgM-positive individuals. The statistical analysis was performed with a 5% significance level.
Among the 423 children, 107 (25.3%) exhibited seroprevalence, with IgG, IgM, or IgG/IgM. Among 854 adolescents, 250 (29.2%) had positive serology, and among 282 adults, 59 (20.9%) were positive. The frequency of positivity on RT-PCR for SARS-CoV-2 was 3.5%, 3.6%, and 6.0 respectively in children, adolescents, and adults. Children had a lower incidence of symptoms than adolescents (p = 0.001) or adults (p = 0.003); the most frequent were fever, ageusia, anosmia, headache, dry cough, sore throat, muscle pain, runny nose, dyspnea, and diarrhea.
We concluded that the prevalence rate for all groups was 26.7% in serology and 4.04% in RT-PCR. Children had lower rates of IgM and fewer symptoms compared to adolescents and adults. The data suggests the potential for transmissibility in all age groups.

Copyright © 2021. Published by Elsevier Ltd.