452— Potential Impacts of Basic Reproduction Number on the COVID-19 Epidemic

The basic reproduction number (R₀) of a disease can be thought of as the number of cases that one case will directly generate if the rest of the population is susceptible to infection. The R₀ of COVID-19 has recently become clearer; toward the beginning of the outbreak, the Imperial College Group estimated it to be somewhere between 1.5 and 3.5 (Imai et al. 2020), but they have now assumed a value of 2.4 (Ferguson et al. 2020). Using the Watts-Strogatz small-world model, I examined the effects of different R₀ values within the original range on the maximum number of individuals infected at a time, the length of the epidemic, and the total number of individuals infected. Results indicate a critical point at R₀ = 2.25 where there is a significant, detrimental change in each of these epidemic measures. With the R₀ of COVID-19 at 2.4, this raises concerns for the spread of Coronavirus throughout our population. With an R₀ value greater than 2.25, my model suggests that the virus will run through the majority of our population very quickly with many cases at once, overwhelming hospitals. Evidently, this is the situation that we are currently witnessing and attempting to control.