What is a flu shot?
The flu shot, or influenza vaccine, is a mixture of dead flu viruses that prepares the immune system to fight the actual virus if it enters the body. It’s like giving a search-and-rescue dog a shoe to sniff so that the dog remembers the scent and can find the owner of the shoe. The immune system remembers the viruses in the flu shot, and is ready to attack if one shows up in your body. The viruses are destroyed quickly, before you come down with any symptoms. Getting the shot does not guarantee that you won’t get the flu, but it does mean that you have a much smaller chance of getting sick from it.