Estimation of Reproduction Number of Influenza in Greece using SIR Model

Infectious disease models are regularly used by epidemiologists to predict the course of diseases. However, the accuracy of such models remains hotly debated. In this study, we developed an algorithm to estimate the contact rate and the average infectious period of influenza using a Susceptible, Infected, and Recovered (SIR) epidemic model. The parameters in this model were estimated using data on infected Greek individuals collected from the National Public Health Organization. The data interval investigated spans 13 weeks of 2019 and the first 8 weeks of 2020. After estimating the nonlinear SIR epidemic model’s parameter values, we computed the theoretical influenza reproduction number and simulated the evolution of the three SIR variables over time. We hypothesized that the reproduction number would be greater than one, which means that influenza is not like other simple diseases but is an epidemic. Our model labeled influenza as an epidemic with a basic reproduction value greater than one.