Measles outbreaks in the U.S. and abroad are raising health experts’ concern about the preventable, once-common childhood virus.

One of the world’s most contagious diseases, measles can lead to potentially serious complications. The best defense, according to experts? Get vaccinated.

Here’s what to know about the year — so far — in measles.

How many measles cases has the U.S. seen this year?

Nationwide, measles cases already are nearly double the total for all of last year.

The U.S. Centers of Disease Control and Prevention documented 113 cases as of April 5. There have been seven outbreaks and most of U.S. cases — 73% — are linked to those flare-ups.

Still, the count is lower than some recent years: 2014 saw 667 cases and 2019 had 1,274.

Why is this a big deal?

The 2019 measles epidemic was the worst in almost three decades, and threatened the United States’ status as a country that has eliminated measles by stopping the continual spread of the measles virus.