(NEXSTAR) – One of the most contagious viruses in the world is spreading around the United States. So far in 2025 there have been three distinct measles outbreaks and at least 164 cases reported to the Centers for Disease Control and Prevention coming from nine states.

The largest of the outbreaks is in West Texas, where the total number of people diagnosed with measles grew to 146 on Friday. An unvaccinated child in the region died last week. It was the first measles death in the U.S. since 2015.

While the focus in recent weeks has been on Texas, eight other states have confirmed cases of the virus, the CDC reports. Nine cases have been confirmed in New Mexico’s Lea County, and at least one case has been confirmed in Alaska, California, Georgia, Kentucky, New Jersey, New York and Rhode Island.

Twenty percent of the reported cases have required hospitalization, according to the CDC. Most of those infected have been children.

The virus is airborne and spreads easily when an infected person breathes, sneezes or coughs.

“On average, one infected person may infect about 15 other people,” said Scott Weaver, a center of excellence director for the Global Virus Network, an international coalition. “There’s only a few viruses that even come close to that.”

Measles then spreads from the respiratory tract throughout the body, causing a high fever; runny nose; cough; red, watery eyes; and a rash.

Measles isn’t usually deadly, but it can have serious complications, especially for young children. Among kids with measles, about 1 in every 20 develops pneumonia, which can be fatal. About one in every 1,000 also suffers swelling of the brain called encephalitis which can lead to convulsions, deafness or intellectual disability.

How can you prevent measles?

The best way to avoid measles is to get the measles, mumps and rubella (MMR) vaccine. The first shot is recommended for children between 12 and 15 months old and the second between 4 and 6 years old.

“Before a vaccine was developed in the 1960s, everybody got” measles, Weaver said. “But then when the vaccine came along, that was a complete game-changer and one of the most successful vaccines in the history of medicine.”

There is “great data” on the safety and effectiveness of the vaccine, he said, because it’s been around for decades.

“Any of these outbreaks we’re seeing can easily be prevented by increasing the rate of vaccination in the community,” he said. “If we can maintain 95% of people vaccinated, we’re not going to see this happening in the future. And we’ve slipped well below that level in many parts of the country.”

Vaccination rates have declined nationwide since the COVID-19 pandemic, and most states are below the 95% vaccination threshold for kindergartners — the level needed to protect communities against measles outbreaks.

Adults can also get MMR boosters, even if they had two doses as a child or aren’t sure if they were vaccinated when young. Those who are immunocompromised or who are living in an area with a large outbreak may want to ask their doctor about getting another dose.

“But I don’t think everyone needs to go and run out to their doctor right now if they did receive two doses as a child,” Weaver said. “If people would just get the standard vaccination, none of this would be happening.”

The Associated Press contributed to this report.