THE DUMB, DEADLY anti-vaccination movement has recently been blamed for the largest measles outbreak in the United States in 20 years. The controversy around anti-vaxxers, as they’re called, is that not only are they putting their own children at risk, but that they are putting other people’s children at risk — children who may be too young or too sick to receive a vaccine themselves — by exposing them to their unvaccinated kid.

As more people become vaccinated, we get closer to eradicating certain preventable diseases. But while the problem in the United States with vaccines is appalling, vaccinations are a global issue. Take this map created by Save the Children: it shows which countries have huge amounts of unimmunized children. India, Nigeria, and the Democratic Republic of Congo dominate the map, while other populous countries like China and Brazil are virtually unrecognizable.

Vaccination is important, but it’s importance spreads beyond the United States: public health can’t stop at the borders.