Oregon Trail Diseases: Where Are They Now?

That's OK, edself. I've had measles, chicken pox, and rubella that my kids will never have. Luckily, I've never had mumps or tuberculosis. When I was a kid, people were mainly terrified of polio, and I even knew a few kids who had to live with the aftereffects. So we all took our sugar cubes at school.

Ooops - that comment referred to a comment on the linked site. Sorry!

Sorry you got measles*, but when the MMR was first introduced in the United States, kids only got one dose, and it seemed to work pretty well - because most kids subsequently got exposed to wild measles, giving them a nice booster effect. Once the rate of measles really dropped, it became clear that one dose of the vaccine, minus exposure to the disease, did not give good protection - which is why we now give two doses.

Why dredge up this old history? Because exactly the same thing happened very recently when the chickenpox vaccine was introduced in the US. It had been used for twenty years in Japan, where only high-risk individuals got the vaccine - one dose worked great, because there was still a lot of chickenpox circulating, so everybody got the booster effect. The Varivax vaccine started in the US as a single dose, just like the MMR. Once the level of wild chickenpox dropped, it became apparent that two doses were needed to give good protection.

Around the world, measles still kills several hundred thousand children a year. I made sure to take my daughters to an old settler cemetery to show them why vaccines are important. Nothing like seeing the tombstones of multiple children in a family, all dying in the same month, to bring home how lucky we are to live in a time when vaccination prevents so many childhood deaths.

* By the way, parents often misdiagnose the various rash-causing infections, which explains most of the cases where people claim to have had chickenpox twice. So maybe it was measles, maybe not.