Explaining the Bomb-Like Dynamics of COVID-19 with Modeling and the Implications for Policy

Gary Lin; Alexandra T Strauss; Maxwell Pinz; Diego A Martinez; Katie K Tseng; Emily Schueller; Oliver Gatalo; Yupeng Yang; Simon A Levin; Eili Y Klein

To assess fit, determine model parameter priors for the model fits, and provide context for the analysis, we conducted a search of all literature already published on the biology and transmission of COVID-19. The majority of this literature was on pre-print servers such as medRxiv, bioRxiv and SSRN's First Look (Table 1) , and most data estimates were reliant upon small studies with wide variability. From this literature, we found an estimate for the incubation period, defined as the time from exposure to onset of illness, of 4.8±2.6 days [25] . The proportion of the population with no/mild/moderate symptoms was estimated to be as high as 85% of the population [26] . The infectiousness period, γ, was estimated to be 4.9 days (95% CrI: 3.3 -5.9) based on the dynamics of earlier coronaviruses, though symptomatic and hospitalized cases likely have a longer recovery time than mild/asymptomatic cases [27] . Finally, we estimated the transmission rates, β1 and β2, based on calculations of the basic reproduction number, 0 , of COVID-19 and clearance estimates. Values for 0 in the literature range from 1.4 to 7.1 [11, [28] [29] [30] ; given these values we assumed that the transmission rate for β was likely between 0.1 and 0.9.