**4.2 SARS-CoV-2 diffusion**

As far as we know, the basic system of SARS-CoV-2 infection is transmission from person to person by air (aerosols) or by direct person-to-person contact. This is why the main preventive action is keeping distance between people, a measure that has a relevant impact on society.

Because of the limited viability of the virus on surfaces, the risk of contamination by coming into contact with an infected surface and then running your hand over your mouth, nose, and possibly eyes is restricted primarily to those surfaces and objects that are very frequently touched by people (e.g. handles, counters, push buttons, etc.).

The incubation period of COVID-19 is estimated between 2 and 14 days [1, 7].
