A child has died of measles in Texas, officials said — the first death from the highly contagious disease the United States has seen in a decade. The school-age child was not vaccinated, according to the Texas Department of State Health Services.

Measles was thought to be eliminated two decades ago. But growing mistrust in vaccines has changed that, and now some people may need booster shots for protection.

People who were vaccinated against measles as a child are considered less likely to become infected with the highly contagious respiratory illness. Vaccinated adults who face greater exposure to measles, such as some health care professionals, may consider getting a booster.

The majority of the 124 measles cases reported in Texas this year have been in children between five and 17. The first death in an ongoing measles outbreak has been reported in Texas. The Texas Department of State Health Services announced the death of a school-aged child on Wednesday morning.

The West Texas measles outbreak continues to grow, now possibly spreading into the central part of the state and neighboring New Mexico, health officials said Friday.

Here’s what to know about the current measles outbreak, how common the measles is in the U.S., how it spreads and what the symptoms and treatment are.

Infectious disease experts say the latest outbreak is still in its infancy and could get a lot worse – here’s what to know