2 things: Getting a virus can really only happen if you're getting the type of vaccine made from what they call in the industry "live attenuated (ie weakened) virus. This vaccine is made from a virus like particle proprietary VLP technology which may make vaccination more possible for stuff that was traditionally difficult to create vaccines for like norovirus and (more significantly from a non emet point of view) Dengue Fever which causes many mosquito related illnesses in the developing and 3rd world in tropical climates. Second, I heard there are two versions, an inhaled mist (nasty but better than vomiting for sure) and a normal injection, where the mist is further along in clinical trials than the shot. That's what I have heard. In either case, I'd say if you got noro right after the vaccine it was not really norovirus or you were already infected before you got the vaccine, or before it could take effect, same as the flu vaccine now (except the flu mist which IS live attenuated, that's why it's not used for people with weaker immune systems).