A simplified estimate of the Effective Reproduction Number $R_t$ using its relation with the doubling time and application to Italian COVID-19 data

TL;DR

This paper introduces a simplified method to estimate the Effective Reproduction Number ($R_t$) for COVID-19 by relating it to the doubling time, using local exponential fits and considering gamma distribution assumptions.

Contribution

It provides a straightforward analytical approach to estimate $R_t$ from doubling time data, enhancing real-time epidemic monitoring.

Findings

The method effectively estimates $R_t$ from doubling time data.

Analytical solutions are derived for gamma-distributed generation times.

The approach is applicable to Italian COVID-19 data.

Abstract

A simplified method to compute $R_t$, the Effective Reproduction Number, is presented. The method relates the value of $R_t$ to the estimation of the doubling time performed with a local exponential fit. The condition $R_t = 1$ corresponds to a growth rate equal to zero or equivalently an infinite doubling time. Different assumptions on the probability distribution of the generation time are considered. A simple analytical solution is presented in case the generation time follows a gamma distribution.