Pediatric COVID-19 patients in South Brazil show abundant viral mRNA and strong specific anti-viral responses
Tiago Fazolo, Karina Lima, Julia C. Fontoura, Priscila Oliveira de Souza, Gabriel Hilario, Renata Zorzetto, Luiz Rodrigues Júnior, Veridiane Maria Pscheidt, Jayme de Castilhos Ferreira Neto, Alisson F. Haubert, Izza Gambin, Aline C. Oliveira, Raissa S. Mello, Matheus de Bastos Balbe e Gutierres, Rodrigo Benedetti Gassen, Laís D. Coimbra, Alexandre Borin, Rafael Elias Marques, Ivaine Taís Sauthier Sartor, Gabriela Oliveira Zavaglia, Ingrid Rodrigues Fernandes, Helder I. Nakaya, Fernanda Hammes Varela, Márcia Polese-Bonatto, Thiago J. Borges, Sidia M. Callegari‐Jacques, Marcela Santos Corrêa da Costa, Jaqueline de Araujo Schwartz, Marcelo Comerlato Scottá, Renato T. Stein, Cristina Bonorino
Abstract
Abstract COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children’s non-specific immune profile is dominated by naive lymphocytes and HLA-DR high CX3CR1 low dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8 + TNF + T cells responses to S peptide pool but stronger responses to N and M peptide pools. Finally, viral mRNA is more abundant in pediatric patients. Our data thus support a scenario in which SARS-CoV-2 infected children contribute to transmission yet are less susceptible to COVID-19 symptoms due to strong and differential responses to the virus.