id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-349073-66ulqu11	Tindale, Lauren	Transmission interval estimates suggest pre-symptomatic spread of COVID-19	2020-03-06		.txt	text/plain	4874	345	60	Conclusions: Estimated serial intervals are shorter than incubation periods in both Singapore and Tianjin, suggesting that pre-symptomatic transmission is occurring. https://doi.org/10.1101/2020.03.03.20029983 doi: medRxiv preprint Our serial intervals are notably shorter than our incubation period estimates, suggesting that there is pre-symptomatic transmission, with infection occurring on average 2.89 and 2.55 days before symptom onset of the infector (Tianjin, Singapore). In both sets of estimates, samples of the incubation period minus serial interval are negative with probability 0.8 or higher (Tianjin) and 0.7 or higher (Singapore), suggesting that a substantial portion of transmission may occur before symptom onset (see Supplementary Information and Figure S2 ), consistent with the clinical observations reported by Rothe et al. Here we use transmission clusters in two locations where cases have reported links, exposure and symptom onset times to estimate both the incubation period and serial interval of COVID-19.	./cache/cord-349073-66ulqu11.txt	./txt/cord-349073-66ulqu11.txt