Viral evolution and the competitive exclusion principle

Consider N virus strains. They have to compete within the host (direct competition) and for infecting hosts in a population (indirect competition). Let R0c(i) be the basic reproduction number of strain i within the host (subscript c stands for cell). Let R0p(i) (subscript p stands for population) be the basic reproduction number of the virus in a host population. We present a simple model that suggests that all the virus strains can coexist only if R0c(1) > R0c(2)…… and R0p(1) < R0p(2), that is, for two strains, the winning strain within the host is the loser between hosts.