Maximum entropy method for estimating the reproduction number: An investigation for COVID-19 in China

Yong Tao

Despite this, the epidemic still spread throughout the entire country. By March 12, 2020, controlling the spread of the epidemic has become a global challenge. One of the key parameters in epidemic models is the basic reproduction number 0 , defined as the number of secondary infections that arise from a typical primary case in a completely susceptible population [5] . As an infection is spreading through a population, it is more convenient to work with an effective reproduction number , which is defined as the number of secondary infections that arise from a typical primary case [5] . The magnitude of is a useful indicator for evaluating the risk of an infectious disease and the validity of controlling the epidemic. If exceeds 1, the number of incident cases will inevitably grow over time, and a large epidemic is possible. To prevent the expansion of an epidemic, must be reduced to a level below 1. Using the parameter , one can establish the susceptible-infectious-removed (SIR) epidemic model as below [6] [7] [8] :