Comprehensive Glossary for NCCID Terms

The incubation period generally refers to the period of time between infection and the onset of symptoms. The incubation period often overlaps the latent period of a disease.

The latent period (synonyms: exposed period, latency period) is generally considered as the period of time that starts with exposure to a virus and ends when symptoms first appear. The latent period is often considered the incubation period of the virus and the person is not generally infectious at this time.
 
In some instances, the latent period only begins once the virus becomes active, as some viruses are not immediately viable and multiplying following exposure. In other cases, it is when a person becomes infectious that the latent period ends, as some infected people or diseases may be asymptomatic.
 
These distinctions may be important when considering post exposure prophylaxis.