Facebook is taking new steps to stop the spread of misinformation about vaccinations. The social media platform is launching educational pop-up windows that will appear when users search for vaccine related content.

They will contain links to the Center for Disease Control and Prevention users in the U.S. and to the World Health Organization for other parts of the world.

The move comes as the number of people sickened by measles in the U.S. this year climbs to 1200.