A measure of a pathogen’s transmissibility. Reproduction Number is the average number of secondary cases arising from a Primary case in an entirely susceptible population (called basic Reproduction Number, R0), or the average number of secondary cases arising from a Primary case in a population comprised of both susceptible and non-susceptible individuals (called effective Reproduction Number, R or Rt). Basic Reproduction Number (R0) can be obtained with the following equation: (R0 = B*T), where B = beta, effective contacts per duration of time; T = mean infectious time. R0 is often used in deterministic compartmental models to investigate whether a disease will generate an epidemic (R0 > 1), remain endemic (R0 = 1), or be eliminated (R0 < 1). Effective Reproduction Number can be estimated with the following equation: R = R0*x, where x = proportion of susceptible individuals in the population of interest.
