Why are measles outbreaks becoming more common in certain regions?

Measles outbreaks are becoming more common because some people stop protecting themselves from a sickness they used to know well.

Imagine your favorite toy is a robot that can fight off germs, but if you don’t use it, the germs come back and take over. That’s kind of what happens with vaccines. When most kids get shots for measles, the germs stay weak because they can't find enough people to spread them to.

But when many kids skip the shot or don’t get all their shots, the germs become stronger again, like a robot that has been sitting in a closet and now is ready to fight back.

In some areas, not as many people are protected, so the germs can move around more easily. It's like a game of tag, if fewer kids are playing, it’s easier for the tagger to catch everyone.

Also, sometimes kids who aren’t vaccinated get sick and spread the germs to other kids who didn’t get their shots yet. That starts a chain reaction, just like when one kid sneezes in class and suddenly everyone is coughing!