system
Given the following post, respond as if you're commenting on Reddit:
human
Why are we immune to some diseases like chickenpox after having it, but not others like strep throat?

Chickenpox is caused by the varicella-zoster virus and once you get it, you can't get it again because your body has produced the antibodies to fight it. Why is this not the case with strep throat which is caused by either a bacteria or a virus? Can you get sick from the same virus more than once?
gpt
Because strep throat and flu like viruses mutate much more often that many other viruses. Once you get the flu you're immune to that certain flu virus but by next year it will have mutated and a new flu virus will come around that you're not immune to yet.