There are 2 types of flu vaccine: a shot and a nasal spray.
Each has small, but different, risks. The flu shot, which includes a killed version of the virus, cannot give anyone the flu. But since it is grown in eggs, it can cause an allergic reaction in people with egg allergies. The second type of flu protection comes as a flu vaccine nasal spray called FluMist. This spray does contain live virus, so there is a small chance it could cause flu infection in someone with a compromised immune system. Via New York Times.