Leukopenia of Asymptomatic COVID-19 Infections under 18 Years Old in Recovery Stage (Running head: Leukopenia of Asymptomatic COVID-19 Infections)

Objectives In December, 2019, a type of novel coronavirus which was designated novel coronavirus 2019 (2019-nCoV) by the World Health Organization (WHO) occurred in Wuhan, Hubei, China. There is limited information available on the epidemiological and clinical characteristics of patients under 18 years old in the recovery stage. To compare the difference of epidemiological and clinical characteristics of COVID-19 involving 25 patients under 18 years old in the recovery stage between confirmed and asymptomatic infections. Methods The retrospective, single-center cohort study of COVID-19 involving 25 patients under 18 years old in the recovery stage at Guizhou Provincial Staff Hospital in Guiyang, China, from January 29 to March 31, 2020; last date of follow-up was April 22. We collected and analyzed epidemiological, demographic, clinical, laboratory, radiological, and treatment data. The researchers compared the epidemiological and clinical characteristics of confirmed COVID-19 infections and asymptomatic infections. Results Among the 25 COVID infections under 18 years old, 16 (64%) were mild or moderate confirmed cases, and 9 (36%) were asymptomatic. The shortest treatment period was 6 days, the longest 26 days, and the average treatment period was 14 days. Four cases (44.4%) had visited Wuhan or had a living story in the city. There were 9 (100%) asymptomatic cases were familial cluster outbreak, with an average infection number was 6 cases among all families. The number of asymptomatic COVID-19 infections with leukopenia was significantly more than confirmed cases ( p  = 0.04). Conclusions Leukopenia mostly occurred in asymptomatic COVID-19 infections under 18 years old compared with the confirmed patients. Trial registration: The Chinese Clinical Trial Register (CCTR number: ChiCTR2000032458) registered this study retrospectively on 28 April 2020.