Maricopa County health officials have confirmed 21 measles cases in 2026, marking a significant rise from the 30-year annual average of one case. Authorities are currently investigating potential public exposures at Tempe Marketplace and a Walmart in Surprise, urging anyone who visited those sites to monitor for symptoms.
Measles Cluster and Public Exposure Sites
The Maricopa County Department of Public Health (MCDPH) is responding to a new cluster of measles cases linked to a business in the unincorporated community of Aguila. While officials have not explicitly confirmed whether this specific cluster is tied to two recently announced exposure sites in the Phoenix metropolitan area, the surge in cases has prompted urgent public health warnings. Aguila is located along U.S. 60, approximately 91 miles northwest of downtown Phoenix.
MCDPH officials released the following details regarding potential exposure locations:
- Tempe Marketplace, 2000 E. Rio Salado Pkwy, Tempe: Monday, July 6, from 5 p.m. to 8:30 p.m. Individuals present at this time should monitor for symptoms through July 27.
- Walmart, 13770 W. Bell Rd., Surprise: Sunday, July 12, from 2 p.m. to 6 p.m. Individuals present at this time should monitor for symptoms through Aug. 2.
Regional Context and Health Risks
The 21 confirmed cases in Maricopa County contribute to a broader resurgence of the virus across Arizona, which has reported a total of 117 confirmed cases in 2026. Beyond the Phoenix area, an additional measles case was reported in Yavapai County, and the virus was recently detected in a wastewater treatment facility in Sedona. Federal officials at the CDC noted that 1,792 confirmed measles cases have been reported nationwide as of April, with numbers expected to rise.
Measles is a highly contagious respiratory virus. According to public health authorities, the virus can linger in the air for up to two hours after an infected person has coughed or sneezed. Approximately 90% of unvaccinated people exposed to the virus will become infected. Data from the Arizona Department of Health Services indicates that 96% of Arizona’s recent cases have occurred among unvaccinated individuals.
Symptoms and Clinical Guidance
Symptoms of measles typically appear seven to 12 days after exposure, though they may take up to 21 days to manifest. Clinical signs include:
- High fever (above 101 degrees)
- Red, watery eyes
- Cough
- Runny nose
- A red, raised, blotchy rash that often begins on the face or hairline and spreads down the body
Health officials advise that there is no specific treatment for measles. Complications can include ear infections, pneumonia, diarrhea, or encephalitis—an inflammation of the brain that can cause permanent brain damage. In rare cases, patients may develop subacute sclerosing panencephalitis, a progressive brain disorder that may not appear until years after the initial infection. Severe cases can lead to hospitalization or death.
The disease is preventable with two doses of the measles, mumps, and rubella (MMR) vaccine, typically administered during childhood. Individuals born before 1957 or those who had measles as children are generally considered immune. Those who develop symptoms are advised to stay home and contact a health care provider for guidance. Additional information is available on the MCDPH website.
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