This is a basic simulation of the spread of COVID-19. The simulator is designed to help people understand a few basic principles of how COVID-19 spreads and the public health steps used to stop it.
Grey balls represent people who are vulnerable to the virus.
When people are infected by the virus, they develop cough, fever or other symptoms and can spread the virus through contact with others. The red balls represent infected people who have symptoms and are spreading the virus.
After people recover from the virus, they are usually immune, at least for a short time. The virus and a vaccine for the virus both create immunity. The blue balls represent people who have recovered from the virus and are immune.
Some viruses are more contagious than others. The Reproductive Number R of the virus is the number of people one person with the disease can be expected to share it with. COVID-19 has an initial R of about 2.4. Each person with the disease infects an average of 2.4 other people when most of the population is vulnerable. In the simulation below, press start and watch how the epidemic spreads from person to person. Each second is two days. The timer shows how many days it takes for the epidemic to run through the community until there are no more cases, and the total shows how many uninfected people and how many infected (immune) people are present at the end of the epidemic. As the simulation progresses, watch what happens to the R-effective display on the right. Leave the setting for walls at 0% for this run.