how long are you contagious after a stomach flu
So, if people don't wash their hands well after using the bathroom, they can spread the germs to others before they even know they are going to get sick. People are contagious for at least 3 days after all stomach flu (viral gastroenteritis) symptoms have completely stopped and they feel perfectly fine2.hey were well by December 20. They had relatives come visit for Christmas on December 26 (1 week later). 3 of the visitors came down with the same stomach virus starting about 36 hours after arriving. My in-laws never got sick again since it was the same virus they just had. So, 1 week is NOT long enough to wait.