Infectivity

Not to be confused with Injectivity.

In epidemiology, infectivity is the ability of a pathogen to establish an infection. More specifically, infectivity is the extent to which the pathogen can enter, survive, and multiply in a host. It is measured by the ratio of the number of people who become infected to the total number exposed to the pathogen.^[1]

Infectivity has been shown to positively correlate with virulence, in plants. This means that as a pathogen's ability to infect a greater number of hosts increases, so does the level of harm it brings to the host.^[2]

A pathogen's infectivity is different from its transmissibility, which refers to a pathogen's capacity to pass from one organism to another.^[1]

See also

• Basic reproduction number (basic reproductive rate, basic reproductive ratio, R₀, or r nought)