My son had the stomach virus on sunday and it is now thursday and no one else has gotten it yet so are we in the clear? have a fear of vomiting. thanks

4 days = maybe safe: Contagiousness varies among different "stomach viruses" and among different people, so is not easily predictable. However, one can feel safer if the sick person wakes up on Day 5 without any symptoms the preceding 4 days. If unlucky, she can still catch a virus and come down with the illness. Food poisoning is usually less contagious, but depends on the bacteria type.