The basic reproduction number or simply the reproduction number (R0) is the average number of secondary infections produced by one infected computer node during the mean course of infection in completely susceptible nodes. If R0 < 1, then on average,the number of new infections by one infected node over the mean course of the malicious code is less than one, which implies that the infection disappears eventually. If R0 > 1, then the number of new infections produced by one infected node are greater than one, which leads to the persistence of the infection.