Epidemiology

About this model

This diagram models a simple epidemic spread mechanism, simulating the infectious process, recovery, and immunization dynamics within a population. It includes three main pools representing the states of individuals within the population: "Susceptible" for those who have not yet contracted the disease, "Infectious" for those currently infected, and "Recovered / Immune" for individuals who have either recovered and gained immunity or have been vaccinated against the disease. Resources, in this context, stand for individuals moving through these states according to the mechanisms defined by the connections and nodes.

The process begins with a set number of infectious individuals and a large susceptible population. As the simulation progresses, susceptible individuals are exposed to the virus, represented by resource flows modulated by a register calculating "Infection chance per susceptible host" and gates determining who becomes infected ("Contract?") or recovers ("Recover?"). There's also a vaccination process modeled, where a certain number of susceptible individuals are daily moved to the "Recovered / Immune" pool, simulating the effect of vaccination on the overall dynamics. The flow rates, including the percentages of infection spread and recovery, are manipulated by state connections adjusting according to the register's output, reflecting how the infection probability impacts the movement of individuals through the states. This setup provides a framework for understanding how various factors, including vaccination efforts and infection rates, influence the spread of an epidemic through a population.

"Epidemiology" is a public Machinations diagram shared in the Community by Catalin Ichim, with 21 components.

It was created in March 2024 and last edited in November 2025.

Open the diagram in the Machinations app and press Play to watch the resources move, adjust its values to test how the system responds, or remix it to make an editable copy in My diagrams.