FILE – Signs point the way to measles testing in on Feb. 27, 2025, in Seminole, Texas.
A third state is now part of the growing measles outbreak in the U.S.
On Tuesday, health officials in Oklahoma reported two “probable” cases in the state that appear to be linked to the ongoing outbreak in Texas and New Mexico.
According to the Oklahoma State Department of Health, the two people developed measles symptoms after exposure to cases associated with the Texas and New Mexico outbreaks.
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The individuals isolated immediately after they realized they had been exposed and stayed home throughout the period they were contagious, health officials said.
The two cases come as the outbreak in West Texas continues to grow.
On Tuesday, the Texas Department of State Health Services said that 223 measles cases had been confirmed in the state, up from 198 last week. The New Mexico Department of Health reported 33 cases, up from 30, in Lea County, which borders Texas.
Many of the cases developed in unvaccinated children.
“One of my concerns has been around travel,” said Katherine Wells, director of public health at the health department in Lubbock, Texas. “Communicable diseases do not know borders.”
Lubbock is the city where most of the hospitalized children in the outbreak have been treated.
Measles is one of the most contagious viruses on Earth. Unvaccinated people are most at risk for becoming infected, getting sick enough to be hospitalized and die from the virus.
Measles can be prevented with two doses of an MMR vaccine. The first shot is recommended around age 1, and the second shot at the beginning of kindergarten. Two doses are about 97% effective at preventing measles.
Other individual cases unrelated to the West Texas outbreak have also been reported this week, in patients in Maryland and Vermont who had traveled overseas.
“Everybody’s on high alert,” Wells said.
This story first appeared on NBCNews.com. More from NBC News:
