Quantifying the roles of vomiting, diarrhea, and residents vs. staff in norovirus transmission in U.S. nursing home outbreaks

Carly Adams; David Young; Paul A Gastañaduy; Prabasaj Paul; Zach Marsh; Aron J Hall; Benjamin A Lopman

The primary outcome of interest in this study was individual case infectiousness, which 134 we measured by estimating the reproduction number, R Ei , for each case. Here, R Ei is defined as 135 the number of secondary cases generated by an individual case i. We estimated R Ei using a 136 maximum likelihood procedure to infer the number of secondary cases generated by each case [17, 19, 20] . Briefly, this method calculates, in a statistically rigorous 144 manner, the probability that cases with earlier symptom onset dates infected cases with later 145 symptom onset dates, selects the probabilities that are greatest using the frequency distribution of 146 the serial interval, and then, using these probabilities, determines the number of secondary cases 147 produced by cases with each symptom onset date. Individual cases were assigned a R Ei based on This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license.