R-naught (R0)

The basic reproduction number, R₀, measures how contagious an infectious disease is. It represents the average number of people one infected person will spread the disease to in a fully susceptible population. If R₀ is greater than 1, the infection can grow and cause an outbreak. If it's less than 1, the spread will likely decline and eventually stop. R₀ helps public health officials understand the potential for transmission and informs strategies like vaccination or social distancing to control the spread. It depends on factors like the disease's contagiousness, how people interact, and the duration of infectiousness.