— -- Question: What is a nasal spray flu vaccine, how does it work and what are the side effects?
Answer: FluMist is a nasal spray that is a flu vaccine. It's actually made up of live but weakened flu viruses that allow your body to develop immunity to the flu virus. The most common side effects are sore throat, runny nose, cough. Some people can develop muscle aches or even fever. You cannot get the flu from FluMist.