Pediatric COVID-19 patients in South Brazil show abundant viral mRNA and strong specific anti-viral responses

Nat Commun. 2021 Nov 25;12(1):6844. doi: 10.1038/s41467-021-27120-y.


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-DRhighCX3CR1low 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology*
  • Brazil
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes
  • COVID-19 / immunology*
  • COVID-19 / prevention & control
  • COVID-19 Vaccines
  • Child
  • Child, Preschool
  • Cytokines / blood
  • Female
  • Humans
  • Immunity, Humoral*
  • Immunity, Innate
  • Male
  • Middle Aged
  • RNA, Messenger
  • RNA, Viral*
  • SARS-CoV-2 / genetics*
  • Spike Glycoprotein, Coronavirus / immunology
  • T-Lymphocytes
  • Vaccines, Synthetic / immunology*
  • Viral Structural Proteins / immunology
  • Young Adult
  • mRNA Vaccines


  • Antibodies, Viral
  • COVID-19 Vaccines
  • Cytokines
  • RNA, Messenger
  • RNA, Viral
  • Spike Glycoprotein, Coronavirus
  • Vaccines, Synthetic
  • Viral Structural Proteins