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Basic Reproduction Number




In Epidemiology , the basic reproduction number of an Infection is the mean number of secondary cases a typical single infected case will cause in a population with no Immunity to the disease in the absence of interventions to control the infection. It is often denoted ''R''0 .

When

R


the infection will die out with certainty. But if

R


there is some possibility of a major Epidemic .

Generally, the larger the value of ''R''0, the harder it is to control the epidemic. In particular, the proportion of the population that need to be vaccinated to provide Herd Immunity and prevent sustained spread of the infection is given by 1-1/R0.

Values of ''R''0 of some well-known infectious diseases: