Measles cases have hit a record in the United States not seen since 1991, nearly a decade before the viral disease was declared eliminated.
Cases in California have also swung upward — with twice as many so far this year as in all of last year. Health officials from Los Angeles to San Francisco have been scrambling to respond to measles cases as they emerge, hoping to keep a lid on new infections from travelers before they have a chance to spread.
The grim milestone nationally comes amid a generational setback in controlling the highly contagious disease, which prior to the vaccine era caused millions of infections a year and annually left 400 to 500 people dead, 1,000 with swelling of the brain, and 48,000 needing hospitalization.
Last year, the U.S. recorded three measles deaths: Two victims were unvaccinated school-age children in Texas and one was an unvaccinated adult in New Mexico. They were the first measles deaths in the U.S. since 2015, and the first among children since 2003.
So far this year, there have been 2,318 measles cases reported nationwide, according to the U.S. Centers for Disease Control and Prevention. That’s higher than in any other calendar year since a significant nationwide measles epidemic from 1989 to 1991 led to 55,365 cases over the three years — 17,914 in 1989; 27,808 in 1990; and 9,643 in 1991.
Friday’s milestone was “really disappointing,” said Dr. Yvonne Maldonado, professor of global health and infectious diseases at Stanford University, who a generation ago was on the committee that issued the report in 2000 on the “elimination” of measles from the U.S., which refers to the absence of ongoing disease spread for more than a year.
“Measles is entirely preventable. … This is one of the few diseases that we could actually eradicate from the face of the Earth,” Maldonado said in an interview. “It’s not hard to do, but we just don’t seem to have the political or social will to do it.”
Canada lost its status of having eliminated measles last year, and, according to the World Health Organization, Mexico is among the top 10 countries worldwide with measles outbreaks.
“Halfway into 2026 the U.S. is experiencing the worst year for measles since 1991. We are witnessing an avoidable crisis that disproportionally hurts children,” Dr. Andrew Racine, president of the American Academy of Pediatrics, said in a statement Friday. “These thousands of cases represent real people in communities across the country, including babies hospitalized with pneumonia.”
California has better measles vaccination rates than other states. Still, experts warn that California could be susceptible to bigger outbreaks if the virus happens to find its way into a pocket of unimmunized people.
During the 2024-25 school year, 96.1% of California’s kindergartners were vaccinated against measles — above the goal of 95% to guard against measles outbreaks. But most states fell under that threshold.
“If you have a community of really highly under-vaccinated populations, then you’re at risk for building an outbreak there because there’s just so many people that are susceptible,” Maldonado said.
In California, 52 measles cases have been reported so far this year, more than double the 25 reported in all of last year. Already this year, there have been three measles outbreaks — in Riverside County, Shasta County and another that affected both Sacramento and neighboring Placer counties. The last measles outbreak in California before this year occurred in early 2020.
The most recent outbreak, in the Sacramento Valley, started after an unvaccinated toddler contracted measles after returning from South Carolina — where an outbreak centered in Spartanburg County has been linked to about 1,000 cases, health officials said. It is considered one of the largest outbreaks in the U.S. in more than 30 years.
Officials recommend that babies get their first measles vaccination at 1 year of age, and a second between age 4 and 6. But earlier vaccination is recommended, as early as 6 months of age, for babies about to travel internationally, or to domestic areas where there are measles outbreaks, the L.A. County Department of Public Health said.
Measles outbreaks can quickly spiral out of control if the virus finds its way into a group of unvaccinated people. The Disneyland measles outbreak of December 2014 to April 2015 resulted in 131 cases among Californians, and spread to people in six other states as well as Canada and Mexico. Among the measles cases in California, at least 12 of those infected were infants too young to be vaccinated.
Measles is one of the most highly contagious viruses known to humanity, and 90% of those who are unvaccinated and exposed to it will get the disease, California health officials say.
Nationally, measles vaccination rates have been declining, dropping below the 95% threshold experts say is needed to prevent widespread outbreaks. During the 2024-25 school year, just 92.5% of kindergartners nationally had received the measles vaccine, down from 95.2% during the 2019-20 school year, according to the CDC. More than half of states saw declines in measles vaccinations compared with the year before, the CDC said.
California’s measles vaccination rates among kindergartners remain higher than the 95% threshold. In the 2024-25 year, 96.1% of California’s kindergartners were vaccinated against measles. But there are some counties in which vaccination rates are below the goal; in Southern California, they are San Diego and San Bernardino counties, which have measles vaccination rates of 93.7% among kindergartners.
Other counties with rates below 95% are Calaveras, Del Norte, El Dorado, Glenn, Humboldt, Kern, Nevada, Santa Cruz, Shasta, Sierra, Sutter, Trinity and Tuolumne.
Of the measles cases reported nationally this year, 93% have occurred among people who were unvaccinated or had an unknown vaccination status, the CDC said. Of those infected, 49% were age 5 to 19 and 20% were younger than 5. More than 150 measles patients this year have had to be hospitalized.
The surge in measles comes as the nation’s top health agency, the Department of Health and Human Services, is led by a vaccine skeptic, Robert F. Kennedy Jr.
Earlier this year, Kennedy defended his record, telling a congressional committee that “there’s a global measles epidemic. We’ve done better in preventing it than any country in the world.” His critics have charged that Kennedy has spread misinformation about the safety of the measles vaccine.
“The anti-vaccine rhetoric you ran on and the anti-vaccine actions you have taken over the last year clearly correlates with the dramatic increases, again, in preventable diseases,” Rep. Linda T. Sánchez (D-Whittier) told Kennedy at a House committee hearing.
Kennedy has said he is not anti-vaccine.
The measles vaccine is highly effective and widely considered safe among mainstream medical doctors and scientists. “We’ve been essentially using the same vaccine since the 1960s, literally for 60 years,” Maldonado said. “It still works. It is remarkably safe.”
A study co-authored by Maldonado and published in the Journal of the American Medical Assn. in 2025 said that if there is a 50% decline in childhood vaccination in the U.S., there would be 51.2 million cases of measles over a 25-year period, as well as 9.9 million cases of rubella (which can cause severe birth defects in pregnant women), 4.3 million cases of polio, and 10.3 million hospitalizations and nearly 160,000 deaths.
Experts say the rise of measles comes as misinformation about the vaccine is rampant and is causing vaccine refusal rates to rise.
The American Academy of Pediatrics has accused federal leaders of downplaying the risk of measles and offering misinformation about the vaccine that protects against measles, mumps and rubella.
“Since early last year, federal leaders have dismissed measles as benign and unavoidable and have spread misleading information about the MMR vaccine,” Racine said. “Today, I want to remind parents that measles is not just a rash. The virus can interrupt the immune system’s memory, leaving a previously healthy child significantly more likely to get sick from any type of infection.”
About 1 in 20 children who get measles will get pneumonia; about 1 child of every 1,000 who gets measles will develop swelling of the brain, which can lead to convulsions and cause deafness or intellectual disability; and 1 to 3 of every 1,000 children with measles will die, the CDC says.
People might think about 2,000 measles cases isn’t a big deal, Maldonado said, but noted that measles can spiral upward quickly.
“The more cases you have, the more likely you are going to have kids and immunocompromised people and older individuals in the hospital on ventilators or even dying,” Maldonado said. “I thought we were going to make America healthy again, and one way to do that is to just keep people from getting sick.”
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