Measles outbreaks in Texas and New Mexico are fueling concerns about the rapid spread of the highly contagious virus.

There have been more than 100 measles cases in the United States so far this year, compared to 285 cases in all of 2024. And health officials have warned that they expect more people to fall ill.

The outbreaks come as the rate of childhood vaccinations, including against measles, have fallen. Most of the measles cases in recent outbreaks have been among people who were unvaccinated or whose vaccination status was unknown. Many have been young children, who are at particularly high risk. An unvaccinated child died in Texas from measles, health officials reported Wednesday.

Vaccines are the most effective tools to combat measles. Breakthrough cases — infections among the vaccinated — are extremely rare. But as outbreaks spread, it’s important to review your own vaccination status and make sure you are properly protected.

How to check if you have immunity

More than 90 percent of children in the U.S. have received at least one dose of the shot that protects against measles, mumps and rubella, which is part of the routine child vaccination schedule.

If you are fully vaccinated — meaning you have received two doses at some point in your life — you should be set. Even though immunity from any vaccine wanes over time, the measles vaccine offers strong lifetime protection against infection for almost everyone, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.