id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-278013-0d6o5w8z	Omori, Ryosuke	Ascertainment rate of novel coronavirus disease (COVID-19) in Japan	2020-03-10		.txt	text/plain	1311	101	66	We analyzed the epidemiological dataset of confirmed cases with COVID-19 in Japan as of 28 February 2020 and estimated the number of severe and non-severe cases, accounting for under-ascertainment. The ascertainment rate of non-severe cases was estimated at 0.44 (95% confidence interval: 0.37, 0.50), indicating that unbiased number of non-cases would be more than twice the reported count. Considering that reported cases are usually dominated by non-severe 11 cases, the adjusted total number of cases is also about a double of observed count. Here f a denotes the ratio of non-severe to 1 severe reported case of age group a, as estimated from age-specific severity and 2 incidence rate ratio in China (Guan et al., 2020 , Novel, 2020 . The ascertainment rate of non-severe cases, k, was estimated at 0.44 (95% 10 confidence interval (CI): 0.37, 0.50). The present study estimated the ascertainment-adjusted number of cases in 19 Japan, using age-specific severe fraction of cases.	./cache/cord-278013-0d6o5w8z.txt	./txt/cord-278013-0d6o5w8z.txt