Viral shedding and immunological features of children COVID-19 patients

Background: SARS-CoV-2 could infect people at all ages, and the viral shedding and immunological features of children COVID-19 patients were analyzed. Methods: Epidemiological information and clinical data were collected from 35 children patients. Viral RNAs in respiratory and fecal samples were detected. Plasma of 11 patients were collected and measured for 48 cytokines. Results: 40% (14/35) of the children COVID-19 patients showed asymptomatic infections, while pneumonia shown by CT scan occurred in most of the cases (32/35, 91.43%). Elevated LDH, AST, CRP, neutropenia, leukopenia, lymphopenia and thrombocytopenia occurred in some cases, and CD4 and CD8 counts were normal. A total of 22 cytokines were significantly higher than the healthy control, and IP-10, IFN-α2 of them in children were significantly lower than the adult patients. Meanwhile, MCP-3, HGF, MIP-1α, and IL-1ra were similar or lower than healthy control, while significantly lower than adult patients. Viral RNAs were detected as early as the first day after illness onset (d.a.o) in both the respiratory and fecal samples. Viral RNAs decreased as the disease progression and mostly became negative in respiratory samples within 18 d.a.o, while maintained relatively stable during the disease progression and still detectable in some cases during 36~42 d.a.o. Conclusion: COVID-19 in children was mild, and asymptomatic infection was common. Immune responses were relatively normal in children COVID-19 patients. Cytokine storm also occurred in children patients, while much weaker than adult patients. Positive rate of viral RNAs in fecal samples was high, and profile of viral shedding were different between respiratory and gastrointestinal tract.