WASHINGTON – Measles – declared eliminated in the U.S. in 2002 thanks to widespread vaccination – has hit 22 states this year.
Arizona hasn’t reported a single case during the current outbreak, despite its relatively low vaccination rate. The hot dry climate could be a factor, as could demographics and population density.
But Arizona is no safe haven from the measles.
The state recorded six cases last year, and public health experts say it’s probably a matter of time before Arizona joins this year’s list.
What is the Arizona measles vaccination rate?
Nearly everyone who has contracted measles this year was unvaccinated, according to the Centers for Disease Control and Prevention and state public health authorities. Roughly 12% of Arizona children haven’t had the vaccine by the time they start school.
“Community immunity is highly effective and makes everyone’s protection stronger, especially for those who are immunocompromised,” said Dr. Nick Staab, chief medical officer and epidemiologist at the Maricopa County Department of Public Health.
Public health authorities say 19 out of 20 people must be immunized to confer herd immunity.
Measles targets children under age 5. But only three of the state’s 15 counties have hit the 95% vaccination threshold for kindergarteners: La Paz, Santa Cruz and Yuma. In Yavapai and Mohave counties, one in four kindergarteners haven’t been vaccinated. In Maricopa, it’s one in 10.
Measles is a highly contagious airborne virus.
Symptoms appear between one to three weeks of exposure. Watery eyes, fever, rash, cough and muscle aches are common. Individuals are infectious four days before and four days after the onset of the telltale rash.
Anyone who’s had measles is immune for life. Before the vaccine was introduced in 1963, nearly every child caught it by age 15, according to the Infectious Diseases Society of America.
Arizona demographics factors might make a difference
Arizona’s demographics may have helped to stave off an outbreak. Nearly one in five residents is 65 or older, according to the Census Bureau. Apart from adults with compromised immune systems, young people are the most vulnerable, Staab said. And 21% of the state population is under 18, according to census data.
Measles thrives in crowded spaces with poor air circulation. Phoenix hit 99 degrees on March 25, driving people indoors.
But the state’s population density is low: 63 people per square mile compared to 111 in Texas, according to 2020 Census data. Experts say that might help delay an outbreak, though the hot zones in Texas and New Mexico are in rural areas.
In 2024, the CDC recorded 285 cases of measles across the country.
So far in 2025, the CDC has reported 712 cases through April 11 and three deaths: two in Texas and one in New Mexico. The agency says there are likely many more cases that haven’t been reported.
Most of the cases – 541 – are in Texas, and most of those are in Gaines County in far West Texas, according to state authorities. New Mexico has reported 58 cases, mostly in a county next to Gaines County. Kansas is third, with 32 cases.
Dr. Shad Marvasti, director of Integrative Medicine at HonorHealth and a former professor of public health and preventative medicine at the University of Arizona, suspects that at least one person in Arizona already has contracted measles – either without knowing it or without going to a doctor.
With a growing number of people choosing not to vaccinate and the dense population of Maricopa County, Marvasti says it’s only a matter of time.
There are currently two vaccines for measles, known as MMR and MMRV. Both protect against measles, mumps and rubella. MMRV also includes protection against varicella, the virus that causes chickenpox.
Arizona is among many states with a kindergarten MMR vaccination rate below 90% in 2024, according to the Arizona Department of Health Services. By comparison, the rates in New Mexico and California, which have both seen measles cases this year, topped 95%.
Secretary of Health and Human Services Secretary Robert F. Kennedy Jr. has claimed for years that vaccines cause harm, an assertion widely rejected by public health experts.
As the outbreak spread he has backed away from trying to deter parents from getting their children vaccinated.
On March 2, Kennedy published an essay on the Fox News website encouraging Americans to get the measles vaccine. The HHS website initially linked to that essay, but the link was later taken down.
After the death of a second unvaccinated child in Texas, he became more forceful with the message.
“People should get the measles vaccine but the government should not be mandating those,” he told CBS News after attending the funeral in West Texas.
“I’ll admit, it was a disappointment to hear those words come out of his mouth, but I understand the pressure he’s dealing with as secretary,” said Ursula Conway, president of the Arizona chapter of Children’s Health Defense, an anti-vaccine group that Kennedy founded.
Kennedy has also promoted the use of vitamin A and cod liver oil to treat measles. Physicians in West Texas have reported a spike in vitamin A overdoses involving unvaccinated people who were trying to either treat or ward off measles.
Marvasti suggests consuming vitamin A in a balanced diet as it is found in fish, eggs, leafy greens and root plants like carrots and sweet potatoes.
According to the National Institutes of Health, a vitamin A deficiency can lead to a higher risk of measles. However, it is not a replacement for the vaccine.
The Arizona Department of Health Services suggests two doses of the MMR or MMRV vaccine: the first between 12 and 15 months followed by a booster at age 4 to 6 years.
The department encourages unvaccinated children and adults to get vaccinated as soon as possible.
ADHS says that getting both doses provides 97% protection from measles.
Officials in the counties with the lowest vaccination rates in the state, Mohave at 76% and Yavapai at 75.2%, say they’re concerned. Those rates are even lower than a year earlier, according to AZDHS records.
“There’s always a concern and we want healthy residents, but we do respect the parent’s decision to not vaccinate,” said Dani Lagana, public information officer for the Mohave County Department of Public Health.
The U.S. outbreak remains modest by global standards.
The World Health Organization reported that Romania had 30,692 cases last year out of 127,000 across Europe.
The post Is Arizona’s lack of measles cases a fluke, given its low vaccination rate? appeared first on KTAR.
