This year's flu shot is exactly the same as last year's, but experts say you should get it again anyway. Robert Bettiker, an infectious-disease specialist at Temple University Hospital, said flu viruses change often enough that long-lasting vaccines haven't been essential, although scientists want to develop vaccines that can cover more flu types. One argument for vaccinating everyone every year is that it protects the people who are most vulnerable to flu, but also least likely to have a powerful response to the vaccine. "I'm going to get mine," Bettiker said.