Measles cases in Kansas more than doubled in the last week, bringing the tally to 20, while another outbreak in Ohio has sickened 10 people, local public health officials reported on Wednesday.
There have been several large outbreaks in the United States this year, including one in West Texas that has spread to more than 320 people and hospitalized 40. Health officials have worried that the Texas outbreak may be seeding others.
More than 40 measles cases have been reported in New Mexico, and seven have been identified in Oklahoma. In both states, health officials said the infections were connected to the Texas outbreak.
In Kansas, the virus has mainly infected unvaccinated children in the southwest corner of the state. Genetic sequencing has suggested a link to the Texas and New Mexico outbreaks, state health officials told The New York Times on Wednesday.
Fourteen other states have reported isolated measles cases in 2025, more often the result of international travel. In Ohio, nine of the 10 cases were traced to an unvaccinated man who recently traveled abroad.
“Given the measles activity in Texas, New Mexico and other states around the country, we’re disappointed but not surprised we now have several cases here in Ohio,” said Dr. Bruce Vanderhoff, director of the state’s Department of Health.
Experts fear that declining vaccination rates nationwide have left the country vulnerable to a resurgence of preventable illnesses, including measles.
Just under 93 percent of children in kindergarten had the vaccine for measles, mumps and rubella in the 2023-24 school year, according to the Centers for Disease Control and Prevention.
Experts recommend that at least 95 percent of people in a community be vaccinated in order to avoid outbreaks.
In Kansas, about 90 percent of kindergartners were given the M.M.R. shot in the 2023-24 school year, according to state data.
About 89 percent of kindergartners in Ohio had the M.M.R. shot that year.
Measles, which spreads when an infected person breathes, coughs or sneezes, is one of the most contagious known viruses.
Within a few weeks of exposure, those who are infected may develop a high fever, a cough, a runny nose and red, watery eyes. Within a few days, a telltale rash breaks out, first as flat, red spots on the face and then spreading down the neck and the torso to the rest of the body
In most cases, these symptoms resolve in a few weeks. But in rare cases, the virus causes pneumonia, making it difficult for patients, especially children, to draw oxygen into their lungs.
The infection can also lead to brain swelling, which can cause lasting damage, including blindness, deafness and intellectual disabilities. For every 1,000 children who contract measles, one or two will die, according to the C.D.C.
One child has died in the Texas outbreak, the first such death in the United States in a decade. One suspected measles death was also reported in New Mexico.
