
(AUSTIN, Texas) -- The measles outbreak in western Texas has hit 481 cases, with 59 newly identified infections confirmed over the last three days, according to new data published Friday.
Almost all of the cases are in unvaccinated individuals or in individuals whose vaccination status is unknown, according to the Texas Department of State Health Services (DSHS).
Three of the cases are among people vaccinated with one dose of the measles, mumps, rubella (MMR) vaccine and seven cases are among those vaccinated with two doses.
At least 56 measles patients have been hospitalized so far, the DSHS said.
Children and teenagers between ages 5 and 17 make up the majority of cases, at 180, followed by children ages 4 and under, who account for 157 cases, according to the data.
Gaines County, which borders New Mexico, remains the epicenter of the outbreak, with 315 cases confirmed so far, DSHS data shows.
"We're continuing to see a rise, and so it certainly does tell us that we're not quite in a place yet where the outbreak has been contained," Dr. Sapna Singh, chief medical officer for Texas Children's Pediatrics in Houston, told ABC News in reference to the state data.
"What it does not tell us is how many undiagnosed cases we are potentially missing," she continued. "I suspect that there are greater numbers of patients out there who have infections but may not be seeking out testing and or medical care for symptoms that may not require it."
Singh said the low number of rare breakthrough cases show how effective the vaccine is, and that there are many reasons breakthrough cases might occur, including someone who has a condition that causes their immunity to wane over time.
"Even in those cases, we know that those patients are less likely to develop severe infection, they're less likely to have complications, and they're also much less likely to be the spreaders of the infection, and that is very important in terms of community protection and the protection of vulnerable people in the population," she said.
It comes as the CDC has so far confirmed 607 measles cases in at least 21 states: Alaska, California, Colorado, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont and Washington.
This is likely an undercount due to delays in states reporting cases to the federal health agency.
About 12% of measles patients in the U.S. have been hospitalized, mostly among those aged 19 and under, according to CDC data.
Among the nationally confirmed cases by the CDC, about 97% are in people who are unvaccinated or whose vaccination status is unknown, the agency said.
Of those cases, 1% are among those who received just one dose of the MMR inoculation and 2% are among those who received the required two doses, according to the CDC.
The CDC currently recommends that people receive two doses of the MMR vaccine, the first at ages 12 to 15 months and the second between 4 and 6 years old. One dose is 93% effective, and two doses are 97% effective against measles.
"This is an unfortunate part of just declining vaccine rates, not just within the country, but internationally as well," Singh said. "Many of these other cases that you're seeing in isolated areas, not necessarily large outbreaks, are coming from international travel. … But it is certainly of concern to see the number reach this this high,"
Last year, just 285 cases were confirmed during the entirely of 2024, according to CDC data.
Singh says having more than double the cases in just the first three months of 2025, is "of significant concern" and said it's important to educate people on the importance of vaccination.
"Our greatest defense against the infection is vaccination" she said. "Texas Children's pediatrics, we are really encouraging families to come in speak with their pediatricians if they think their child needs a vaccine, if they think they are due for an additional dose or are unsure about their vaccine status. Your physician, your pediatrician, is going to be the best source for you to get your concerns and questions answered."
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