Clinical characterization, transmissibility, and seroconversion of SARS-CoV-2 infection in children (before the start of vaccination) in the Barcelona Metropolitan Region (Spain)

Abstract

Objective: Analyzing the clinical and microbiological characteristics of coronavirus disease 2019 (COVID-19) infection in children seems essential to determine their role in the etiopathogenesis of the disease. Methods A prospective, longitudinal, and observational study, including children with severe acute respiratory syndrome coronavirus-2 infection, in the Barcelona Metropolitan Region (Spain), was performed. The recruitment pathways were: (1) children who attended a summer school and were included in an active surveillance study and (2) children who were visited in the Emergency Department of Hospital Sant Joan de Déu with symptoms. Close contacts with positive polymerase chain reaction (PCR) results were also included. The children recruited were followed up for 5 weeks. Evaluation of participants included a questionnaire for COVID-19 symptoms, nasopharyngeal swabbing for real-time PCR at 0, 7, and 14 days (weekly repeated up to week 5 if it resulted positive at 14 days), and serology testing at the recruitment and at the fifth week of follow-up. Results: A total of 90 children were recruited, of which 32% were asymptomatic. Transmission was studied in 70/90 children, and in 12 cases (17%), transmission to other children or adults was observed. No clinical or epidemiological differences were found between children who transmitted and those who did not. At the end of the follow-up, 11% of nasopharyngeal PCR remained positive. The serological response was studied in 73/90 children, and 80.82% of children seroconverted. Conclusion: No differences in epidemiological characteristics were found between children who transmitted and those who did not. PCR can be persistently positive for more than 5 weeks. The majority of patients who suffer from the disease produce antibodies against it.