Investigation of a Cluster of 2019 Novel Coronavirus Disease (COVID-19) with Possible Transmission During the Incubation Period--Shenyang City, China, 2020

In December of 2019,a novel coronavirus(2019-nCoV)emerged in Wuhan China,which was later named COVID-19(1).It quickly spread and as of February 11,2020,there were 38,800 laboratoryconfirmed cases,16,067 suspected cases,and 1,113 attributable deaths that have affected all provinciallevel administrative divisions(PLADs)of China's Mainland(2).The first confirmed COVID-19 case in Shenyang City,the capital of Liaoning Province,occurred on January 22,2020,with a total of 9 confirmed cases by January 29,2020.Of these cases,4 were clustered in one family.Shenyang CDC immediately launched an investigation to determine routes of transmission,scale of the outbreak,and evidence for epidemic control.