Evolution is such an important concept for people in general to understand. Bacteria evolve based on environmental factors (like varying levels of antibiotics)

Evolution is such an important concept for people in general to understand. Bacteria evolve based on environmental factors (like varying levels of antibiotics), and that's eventually a very bad thing. Viruses evolve as well, and the nasty viruses that we could eradicate entirely if we had good global vaccination coverage instead -- for a host of often-silly reasons -- get to explode in numbers in various outbreaks. Even if a measles outbreak kills no one, it is still a huge increase in the amount of virus in the wild, and that means faster evolution. I hate to imagine a parent who has been against vaccines (due to being duped by the anti-vaxxers) finding that their own local outbreak was the source for the super-measles virus, which isn't reliably stopped by vaccines and spreads like wildfire, or is more deadly than current strains.