Susceptible-Infected-Recovered model study using free particle dynamics

ABSTRACT

A study on the epidemiological Susceptible-Infected-Recovered (SIR) model is presented using free particle dynamics. The study is performed using a computational model consisting of randomly allocated particles in a closed domain which are free to move in random directions with the ability to collide with each other. The transmission rules for the particle-particle interactions are based on the main viral infection mechanisms, resulting in real-time results of the number of susceptible, infected, and recovered particles within a population of N = 200 particles. The results are qualitatively compared with a differential equation SIR model in terms of the transmission rate beta, recovery rate gamma, and the basic reproductive number R-0, yielding overall good results. The effect of the particle density rho(p) on R-0 is also studied to analyze how an infectious disease spreads over different types of populations. The versatility of the proposed free-particle-dynamics SIR model allows to simulate different scenarios, such as social distancing, commonly referred to as quarantine, no social distancing measures, and a mixture of the former and the latter. It is found that by implementing early relaxation of social distancing measures before the number of infected particles reaches zero, could lead to subsequent outbreaks such as the particular events observed in different countries due to the ongoing COVID-19 health crisis.