Host: Why is a flu shot important? Kathy Reily: Getting a flu shot is important for persons with diabetes because when the blood sugar is elevated the immune system is simply not working as well and the body is not able to fight or defend itself against viruses or bacteria. So, in the fall of the year if you have diabetes we recommend you get the flu vaccine. This will help you give you some extra protection against the flu and during the flu season which usually starts in December and last for a couple of months.