R0

A mathematical term that indicates how contagious an infectious disease is, also known as its reproduction number. Specifically, it is the average number of people who will contract a contagious disease from one person with that disease. For comparison, the R0 value of the 1918 pandemic was estimated to be between 1.4 and 2.8, the common cold at between 2-3, and COVID-19 to be estimated at anywhere from 2-6.