Measles infections in the United States have reached a new high since the disease was declared eradicated in 2000, surpassing 1,500 cases on Sept. 24 with outbreaks growing in parts of Utah and Arizona, public health officials said.

A total of 1,514 measles cases have been confirmed in the United States as of Sept. 24, according to the Centers for Disease Control and Prevention. Though the majority of cases are linked to a large outbreak that originated in West Texas, other outbreaks and cases have arisen from community transmission or during travel in other states.

In recent months, cases in parts of Utah and Arizona have steadily increased. As of Sept. 24, the Utah Department of Health and Human Services confirmed 42 cases, with most infections concentrated in southwest Utah near the Arizona state line.

Meanwhile, the Arizona Department of Health Services has recorded 52 measles cases as of Sept. 23. Of those cases, 48 were reported in Mohave County — a rural area in northern Arizona where the outbreak is centered.

"We expect to see more travelers with measles coming to Utah as measles continues to spread in the United States," the Utah Department of Health and Human Services advised on its website. "Vaccination continues to be the best protection against measles."

Measles is a vaccine-preventable disease that was declared eliminated in the United States in 2000, meaning there was no spread and new cases were contracted only from abroad. But a decline in vaccination rates, with more parents exempting their children from receiving mandated vaccinations, has led to a growing number of states no longer reporting rates consistent with herd immunity and infections returning.

Measles cases in Utah, Arizona

The measles outbreak in Arizona began in and around the town of Colorado City in Mohave County, according to the Arizona Republic, part of the USA TODAY Network. The town is notably known for its connection with Mormon fundamentalism and polygamy, along with the neighboring city of Hildale, Utah.

Last week, the Arizona Republic reported that the outbreak had more than quadrupled in less than a month. Before the outbreak this year, state records showed that Arizona did not have more than 46 measles cases in a year since 1991, according to the newspaper.

In August, the Mohave County Department of Public Health announced that potential exposures may have occurred between Aug. 2 and Aug. 7 in both Arizona and Utah. The state health department advised residents of Colorado City and surrounding areas to stay informed about the disease because it is "currently active" within the community.

The Utah Department of Health and Human Services previously reported in June that a person had traveled to southwest Utah in May while they were infectious with measles and visited public locations. The Southwest Utah Public Health Department then said in July that there was an "unusually high" number of cases of measles and whooping cough in the region.

By September, exposure locations in southwest Utah included high school events, a local festival, and restaurants, according to the Utah Department of Health and Human Services. Health officials in both Utah and Arizona have urged residents to get the measles vaccine.

US measles cases reach new high

Among the 1,514 confirmed measles cases, 1,493 cases were recorded across 41 states, according to the CDC. A total of 21 measles cases were reported among international visitors to the United States.

The last outbreak of a similar scale occurred in 2019, when 1,274 cases were confirmed across the country. By July 2025, measles cases topped that number with 1,288 cases confirmed.

The CDC noted that there have been 40 outbreaks reported in 2025, with 86% of confirmed cases — 1,307 cases — being outbreak-associated. Outbreaks are defined as three or more related cases.

Of the 1,514 cases, 27% occurred in patients under 5, while 39% were reported in those ages 5 to 19, according to the CDC. The agency also reported that 185 patients have been hospitalized, including 88 patients under 5 years of age.

The CDC said 92% of the country's measles cases were in patients who either had not been vaccinated or had an unknown status. There have been three confirmed deaths, including two children, in West Texas.

West Texas was the epicenter of measles cases in the United States, with more than 760 cases confirmed by August. Over two-thirds of infections had occurred in children, and more than 94% of cases were in unvaccinated people.

On Aug. 18, the Texas Department of State Health Services declared that the outbreak in West Texas had ended, saying that it had been more than 42 days, or two incubation periods, since a new case was reported in counties that previously showed evidence of ongoing transmission.

Best protection against measles is the MMR vaccine

Measles is highly contagious and can spread when an infected person coughs or sneezes, the CDC said. People can also be infected by breathing contaminated air, where it remains infectious for up to two hours, or by touching their mouth, eyes, or nose after contact with a contaminated surface.

Measles symptoms typically appear seven to 14 days after contact with the virus and commonly include high fever, cough, runny nose, and watery eyes, according to the CDC. A measles rash appears three to five days after the onset of the first symptoms.

Complications from measles include ear infections, hearing loss, pneumonia, croup, diarrhea, blindness, and swelling of the brain, the CDC said. Even in healthy children, measles can cause serious illness and death.

In unvaccinated pregnant women, measles may cause premature birth or a low-birthweight baby.

The CDC estimates that about 1 in 5 unvaccinated people in the United States who get measles will need hospitalization. Health experts have underscored that the best protection against the disease is the vaccine, either given alone or as part of a measles-mumps-rubella (MMR) shot or a measles-mumps-rubella-varicella (MMRV) vaccine.

Two doses of the MMR vaccine provide 97% protection against the virus, according to the CDC. Children typically first receive the vaccine when they are 12 to 15 months old and again at age 4 to 6 years.

Adults born before 1957 are presumed to have acquired immunity as they most likely had measles during childhood, according to the National Foundation for Infectious Diseases.

Contributing: Adrianna Rodriguez, Janet Loehrke, and Mary Walrath-Holdridge, USA TODAY; Stephanie Innes, Arizona Republic

This article originally appeared on USA TODAY: US measles cases surpass 1,500 as outbreaks grow in parts of Utah and Arizona

Reporting by Thao Nguyen, USA TODAY / USA TODAY

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