Basic reproductive rate
See reproduction number for full article. Basic reproductive rate(R0, basic reproduction number, basic reproductive ratio) is the expected number of secondary cases produced by a typical primary case in an entirely susceptible population. When R0 < 1 the infection will die out but any value for R0 ≥ 1 implies it will spread (without control measures) and higher numbers are more likely to cause epidemics. When control measures are possible epidemiologists are more interested in the effective reproduction number (R).