Royal Society Open Science (Sep 2020)

Super-spreading events initiated the exponential growth phase of COVID-19 with ℛ0 higher than initially estimated

  • Marek Kochańczyk,
  • Frederic Grabowski,
  • Tomasz Lipniacki

DOI
https://doi.org/10.1098/rsos.200786
Journal volume & issue
Vol. 7, no. 9

Abstract

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The basic reproduction number [Formula: see text] of the coronavirus disease 2019 has been estimated to range between 2 and 4. Here, we used an SEIR model that properly accounts for the distribution of the latent period and, based on empirical estimates of the doubling time in the near-exponential phases of epidemic progression in China, Italy, Spain, France, UK, Germany, Switzerland and New York State, we estimated that [Formula: see text] lies in the range 4.7–11.4. We explained this discrepancy by performing stochastic simulations of model dynamics in a population with a small proportion of super-spreaders. The simulations revealed two-phase dynamics, in which an initial phase of relatively slow epidemic progression diverts to a faster phase upon appearance of infectious super-spreaders. Early estimates obtained for this initial phase may suggest lower [Formula: see text].

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