The Centers for Disease Control and Prevention (CDC) has confirmed 228 cases of measles in 12 states so far this year.

The CDC has identified six outbreaks, which it defines as three or mores cases, in New York, Washington, Texas, Illinois and California.

The cases are linked to unvaccinated American travelers bringing measles back into the U.S. from other countries where large measles outbreaks are occurring, like Israel and Ukraine, the CDC says.

Read more at The Hill.