Overlooked in the recent concern over the measles outbreak in the United States is the fact that this is a worldwide problem that requires a worldwide solution, says health care journalist Faye Flam. Writing in Bloomberg, Flam points out that this year Madagascar saw a huge outbreak of the disease that killed 1,200 children. (To put that in context, yesterday the CDC put the number of measles outbreaks in the U.S. at 839; there have been no recorded deaths.)

Flam describes the “canonical pattern” often experienced by developing countries in which they get a supply of the vaccine, inoculate portions of their public, and see rates go way down initially because there’s also natural immunity in play by those who’ve already had the disease.

“But over time, the natural immunity helps less, and the country depends more and more on the vaccine,” Flam writes. “When there’s a high birth rate, the population of unvaccinated, susceptible people can start to grow.”

The answer is to keep up with the vaccines, and vaccination rates. The rate needs to be somewhere between 90% to 95% to avoid future outbreaks (in the U.S. it’s about 91%). But in Madagascar and a number of other countries, the vaccination rates are less than half the children.

“By focusing efforts on developing countries where the outbreaks are many times bigger and deadlier, some scientists think it might be possible to eradicate the virus soon, as they did 40 years ago with smallpox,” Flam writes.