system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If influenza is always mutating, why does getting a flu shot help? Doesn't the shot only prevent attacks from a certain strain?
gpt
Every year the world health organization researches which variation of the flu is going to be most common.  After they come to a decision, the flu shot is made specifically for that virus. The flu shot contains a dead part of the virus that your body can identify and recognize when you actually come in contact with the virus later on.