US surpasses 1,000 measles cases for second time this century

Key takeaways:

• According to the CDC, there have been 1,001 confirmed measles cases in the U.S. this year.
• Andrew T. Pavia, MD, told Healio the true number of cases is likely even higher.

The United States has surpassed 1,000 measles cases for the first time in 6 years, according to the CDC, which reported Friday that there have been 1,001 confirmed cases in 30 states so far in 2025.

Most of the infections (93%) are related to 14 outbreaks of three or more cases, the CDC said. Children make up the majority of cases — 30% have occurred in children aged younger than 5 years and 38% in children aged 5 to 19 years. Adults aged 20 years or older account for 31% of infections.

Only 4% of the cases have occurred among people who received one or two doses of measles vaccine. The other 96% were unvaccinated or had an unknown vaccination status.

“It tells us we are in real trouble,” Andrew T. Pavia, MD, professor of pediatrics and medicine in the division of infectious diseases at University of Utah, told Healio.

“Instead of what has happened in the past where a single case is either contained or leads to just one or two additional cases, we are seeing outbreaks of three or more,” Pavia said.

“That tells us that with the falling rates of immunization — particularly among school-aged kids — we have got a lot of dry tinder on the ground, and every time lightning strikes, there is a chance of a huge forest fire.”

Experts have warned that waning vaccination coverage could lead to the reemergence of measles and other highly infectious diseases such as mumps, rubella and pertussis. CDC data from the 2023-2024 school year showed that only 11 states achieved greater than 95% vaccine coverage — the threshold widely considered necessary to prevent outbreaks. Although most states have maintained vaccine coverage above 90%, 14 reported immunization rates below 90%.

The last time the U.S. saw a measles case count this high was in 2019, when there were 1,274 cases — mostly concentrated in parts of New York City and Rockland County, New York, Pavia noted. That was the only other year this century that the U.S. has hit 1,000 cases.

“Here, we are seeing that there are susceptible populations in communities where vaccination rates are too low to prevent an outbreak … and they are scattered within a given state,” Pavia said. “The pattern now suggests that there is much greater potential for spread in many other parts of the U.S., and that is what we are seeing. Just this week, we added a new outbreak in North Dakota that spread from a single case last week to nine reported [Friday].”

Most of the cases this year have been reported in Texas, where an outbreak in the western part of the state has grown to 709 cases and caused the death of two children. An adult in neighboring New Mexico also died from measles in a related outbreak that has reached 71 cases. All three were unvaccinated, according to health authorities.

California, Kansas, Ohio, Oklahoma and Pennsylvania have reported between 10 and 49 cases so far this year, and two dozen other states have reported between one and nine cases, according to the CDC.

Pavia noted that the true number of cases is likely even higher. The CDC only reports cases that have been confirmed by testing in approved labs, which can take a week or longer after the case was diagnosed at a hospital, he explained.

In states where new infections pop up, Pavia said detecting cases, isolating the patients and vaccinating people who have been exposed can keep measles from spreading.

“Remember that if you have a series of exposures — let’s say a child walks into an elementary school with measles — you have 3 days to vaccinate unvaccinated people, and they will be protected,” he said.

Once outbreaks get as big as the one in Texas, Pavia said it is much more challenging to contain them — and funding cuts from the federal government could inhibit the response even further.

“For areas like West Texas where the virus is spreading quite rapidly, the best strategy you have is to reduce the number of people who are susceptible, and that means pushing on mass campaigns to get people vaccinated,” he said. “It is going to take resources (in public health), it is going to take partnerships with communities, and it is going to take education.”

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Andrew T. Pavia, MD, can be reached at pediatrics@healio.com.