reproduction number

The reproduction number, often called R, indicates how many people, on average, a single infected person will pass a disease to. If R is greater than 1, the disease will likely spread and grow; if it's less than 1, the spread will slow down and eventually stop. It helps us understand the contagiousness of an illness and guides public health measures, such as social distancing or vaccination efforts. Essentially, R measures the potential for an outbreak to grow or decline within a population.