id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-034351-5br4faov	Xu, Shuang-Fei	Cross-Sectional Seroepidemiologic Study of Coronavirus Disease 2019 (COVID-19) among Close Contacts, Children, and Migrant Workers in Shanghai	2020-10-02		.txt	text/plain	3445	187	51	(1) Background: Along with an increasing risk caused by migrant workers returning to the urban areas for the resumption of work and production and growing epidemiological evidence of possible transmission during the incubation period, a study of Coronavirus Disease 2019 (COVID-19) is warranted among key populations to determine the serum antibody against the SARS-CoV-2 and the carrying status of SARS-CoV-2 to identify potential asymptomatic infection and to explore the risk factors. Three categories of targeted populations (close contacts, migrant workers who return to urban areas for work, and school children) will be included in this study as they are important for case identification in communities. Since the first known case of pneumonia infected with the novel coronavirus was reported in the city of Wuhan in late December of 2019, Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2 and announced by the World Health Organization on 11 February 2020, unexpectedly and quickly spread in China and many other countries with rapid geographical expansion and a sudden increase in the number of cases [1, 2] .	./cache/cord-034351-5br4faov.txt	./txt/cord-034351-5br4faov.txt