An epidemic of coronavirus disease 2019 (COVID-19) has spread rapidly throughout China and the world since 2019.As of March 3rd 2020,China had reported a total of 80,304 cases of COVID-19,including 2,946 deaths.Outside China,there are now 10,566 cases in 72 countries and 166 deaths.Of the deaths reported so far,most of them have been elderly men [1-4].Adults are more likely to be infected with novel coronavirus (SARS-CoV-2) than children;and symptoms are relatively milder in pediatric patients than in adult patients.The same conditions occurred during the SARS and MERS outbreaks.It is still not clear why children seem to be escaping the worst effects of the coronavirus infection [5-7].