The U.S. Centers for Disease Control and Prevention is advising those planning to travel internationally to make sure they’re vaccinated against measles. The warning, issued last week, says cases of the highly contagious disease are on the rise around the world.

Measles cases are on the rise in many countries around the world, prompting the U.S. Centers for Disease Control and Prevention to update its travel warning.

The CDC is urging Americans to make sure they’re protected against measles before traveling to other countries this summer.