So if my boyfriend gets the stomach bug, how long till I can kiss him and not get the bug?I know it isn't transmitted via saliva, but it can be by kissing if the person is recently throw up. I'm concerned that he may have vomit particles on his lips or in his mouth even after he is over the illness by a week maximum and we kiss and I get it. So,how long are those vomit particles going to be in his mouth?