Medical professionals in Middle Tennessee are already gearing up for the flu season and urging people to get their flu shots early. They say the earlier the better, because the flu is a virus and can be active any time of the year, not just the colder months. The flu shot takes two weeks to develop these immunities in your system. A shot will last the entire season until the next vaccination is ready around late August 2016. Medical experts say the best means of protection is to get a flu shot. Even if you were to get the flu, your symptoms will be less severe and the overall illness length will be shorter.