An incubation period is the time between a person contracting a virus and their symptoms starting to show. For example, the incubation period of chickenpox is 14-16 days.
The incubation period for coronavirus is between 2 and 14 days from the time of exposure.
In a typical infectious disease, the incubation period signifies the period taken by the multiplying organism to reach a threshold necessary to produce symptoms in the host.
In some diseases, the latency period is longer than the incubation period. After the latency period (but prior to the infection period) the infected person can transmit the disease without signs of any symptoms. Such an infection is called subclinical infection.
While latent or latency period may be synonymous, a distinction is sometimes made between incubation period, the period between infection and onset of the disease, and latent period, the time from infection to infectiousness.
A person may carry a bacteria like Streptococcus in the throat, without exhibiting any symptoms. Depending on the disease, the person may or may not be contagious during the incubation period.
During latency, an infection is subclinical. With respect to viral infections, in incubation the virus is replicating. This is in contrast with viral latency, a form of dormancy in which the virus does not replicate.