No virus is able to live and reproduce outside of a living being (man or animal), but it can survive some time outside (it is believed that the Coronavirus cannot survive more than a few hours outside the host, but the data are still uncertain since CoVID-19 is a new virus and still not sufficiently known and studied).
The true prevention of contagion depends on the probability that people have to come into contact with the viruses emitted by sick subjects or healthy carriers (healthy carriers are those who have been contaminated by the virus without manifesting the symptoms or because it is still early to manifest them or because they will never manifest them by being able to eliminate the virus).