[Epidemiological and clinical features of children with mild coronavirus disease 2019]

To study the epidemiological and clinical features of children with mild coronavirus disease 2019 (COVID-19).

The children who were diagnosed with mild COVID-19 in the Wuchang Shelter Hospital in Wuhan from February 5 to March 10, 2020 were enrolled as subjects. The clinical, laboratory, and lung imaging data were collected during hospitalization and isolation. This was a retrospective single-center case series analysis.

A total of 1 124 patients with mild COVID-19 were admitted from February 5 to March 10, 2020, including 13 children (1.16%). All the 13 children (7 boys and 6 girls) were residents of Wuhan in China, with a median age of 16 years (range: 10-18 years). Of all the 13 children, 9(69%) were from family clusters of COVID-19 and 4(31%) had unknown sources of infection. The mean time from exposure to onset was 6.8 days (range: 2-13 days) in 9 children with a definite history of exposure. There were 6 symptomatic children with the main manifestations of fever, cough, weakness, and myalgia, and the mean time from onset to hospitalization was 9.2 days. Of all the 13 children, 7(54%) were asymptomatic with positive nucleic acid test of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). There were 4 children (31%) with abnormal lung CT findings, mainly patchy shadows or ground-glass opacities in the lung field, and 6 children (46%) had no symptoms with normal lung CT findings. All children had normal routine blood test results and C-reactive protein levels. Eight children underwent SARS-CoV-2 IgM and IgG tests at least once, among whom 6 had negative SARS-CoV-2 IgM but positive IgG, and 2 underwent SARS-CoV-2 IgM and IgG tests twice and had negative results. Of all the 13 children, 11(85%) had negative results of two SARS-CoV-2 nucleic acid tests during hospitalization and were discharged, and 2(15%) had positive results of four SARS-CoV-2 nucleic acid tests and were transferred to another hospital and lost to follow-up. Among the 11 children who were followed up, 1 had positive results of two SARS-CoV-2 nucleic acid tests at the isolation point, and 10 had negative results. The mean hospital stay was 10.9 days for the 13 children. Eleven children recovered during follow-up, with good living and learning conditions.

Children with mild COVID-19 often have an uncertain history of exposure and may not have any clinical symptoms. Etiological diagnosis is more important than clinical diagnosis. The disappearance of clinical manifestations may not parallel with the result of SARS-CoV-2 nucleic acid test. SARS-CoV-2 has a long detoxification time, and there may be recurrent cases of SARS-CoV-2 positivity. Further studies are needed to investigate the production patterns of SARS-CoV-2 IgM and IgG and their effect on the body.