this potent flu bug was a big motivator for 33-year-old corey pershing. >> have a seat. you're here for a flu shot today? >> yes. what i've heard about the h1n1 swine flu, it's mainly people who have been dying from it -- it's scary to think about with two small kids. >> okay, thank you. >> have a great day. >> you too, thank you. >> that's really one of the things about flu is that it's very inpredictable. and that's one of the reasons why we recommend a flu vaccine for everyone is that you never know if you're going to be the one that may end up with more serious disease. >> so we just heard h1n1 is the main strain circulating this year. is it more virulent than other strains, dr. pan? >> so h1n1 is a novel strain that we saw starting in 2009. and it does impact different age groups differently. typically in a seasonal flu season we see most of the deaths and most of the impacts in the over 65. whereas with h1n1, we actually see potentially some level of protection in people over 65 who don't seem to get the serious disease. >> why is that? >> there are a lot of theori