I'm type O and I'm sure I have had noro twice in 23 years, both times I only had v* for one night and once my stomach was empty I stopped. The last time I got sick I'm not really sure if it was noro or not because I only v* once (but I did take like 3 phenergan that night) but I did have d* for like a week, but that's not abnormal because I have tummy problems so it's hard to say.