What the reproductive number R_0 can and cannot tell us about COVID19 dynamics
Abstract
The reproductive number R_0 (and its value after initial disease emergence R) has long been used to predict the likelihood of pathogen invasion, to gauge the potential severity of an epidemic, and to set policy around interventions. However, often ignored complexities have generated confusion around use of the metric. This is particularly apparent with the emergent pandemic virus SARSCoV2, the causative agent of COVID19. We address some of these misconceptions, namely, how R changes over time, varies over space, and relates to epidemic size by referencing the mathematical definition of R and examples from the current pandemic. We hope that a better appreciation of the uses, nuances, and limitations of R facilitates a better understanding of epidemic spread, epidemic severity, and the effects of interventions in the context of SARSCoV2.
 Publication:

arXiv eprints
 Pub Date:
 June 2020
 arXiv:
 arXiv:2006.14676
 Bibcode:
 2020arXiv200614676S
 Keywords:

 Quantitative Biology  Populations and Evolution;
 Physics  Physics and Society
 EPrint:
 25 pages, 2 figures