How COVID-19 progresses from incubation to recovery has implications for everything from how long people may spread it before showing symptoms, to how long people can be expected to occupy resources such as ICU beds and ventilators in hospitals.

Here’s a closer look at what has been learned about how symptoms develop from international studies and interviews with front-line doctors.

Note that the averages represent typical cases, and there tends to be a wide range at all stages of the disease.

Incubation period

The period in which a person is infected but shows no symptoms appears to