Immune response in children with COVID-19 is characterized by lower levels of T-cell activation than infected adults.

Study of immunological features of immune response in 14 children (aged from 12 days up to 15 years) and of 10 adults who developed COVID-19 show increased number of activated CD4 and CD8 cells expressing DR and higher plasmatic levels of IL-12 and IL-1ß in adults with COVID-19, but not in children. In addition, plasmatic levels of CCL5/RANTES are higher in children and adults with COVID-19, while CXCL9/MIG was only increased in adults. Higher number of activated T cells and expression of IL-12 and CXCL9 suggest prominent Th1 polarization of immune response against SARS-CoV2 in infected adults as compared with children.