Phoenix measles exposure warning includes Chase Field and South Phoenix IHOP

Maricopa County health officials are warning people who visited two Phoenix locations that they may have been exposed to measles, including Chase Field and an IHOP in South Phoenix.

The county’s July 21 notice gives separate dates for when people should continue watching for symptoms. Those deadlines are August 2 for the Chase Field exposure and August 3 for the IHOP exposure.

Phoenix exposure locations

• Chase Field, 401 E. Jefferson St.: Possible exposure occurred Sunday, July 12, from 7 p.m. to midnight. People at the ballpark during that period should monitor for symptoms through August 2.
• IHOP, 5020 E. Ray Road: Possible exposure occurred Monday, July 13, from midnight to 3:30 a.m. People at the restaurant during that period should monitor for symptoms through August 3.

Maricopa County officials said the listed time windows include the period during which measles virus may remain airborne. A possible exposure does not mean that every person at either location was exposed or infected.

Local reporting identified the Chase Field window as connected to a Fuerza Regida concert. The county notice concerns a nonresident who tested positive; it does not say the person was a Phoenix resident or that either location became a confirmed transmission site.

Why the warning matters

The county listed six new public exposure locations in its July 21 update and reported 25 confirmed measles cases among Maricopa County residents in 2026 as of that date. The county said that compares with an annual average of one case during the previous 30 years.

The July 21 number is a dated case count, not a current July 28 total. The notice is part of the county’s broader outbreak response and is not a closure order for Chase Field or the IHOP.

What potentially exposed people should do

People who were at either Phoenix location during the listed window should check their written immunization records and contact a health care provider if they are unsure whether they are protected by the measles, mumps and rubella vaccine. Arizona’s myIR system may also help residents locate vaccination records.

Common measles symptoms include a fever above 101 degrees, red or watery eyes, cough, runny nose, and a red, raised, blotchy rash. The rash usually begins near the hairline and spreads downward. Symptoms alone do not confirm measles.

Anyone who develops symptoms after a possible exposure should stay home and call a health care provider before arriving. The caller should identify the possible measles exposure so the office can provide instructions that reduce the risk of exposing other patients.

CDC guidance distinguishes routine vaccination from time-sensitive post-exposure options. In some circumstances, MMR vaccine may be used within 72 hours of exposure, while immunoglobulin may be considered within six days. Those options depend on individual circumstances and should be discussed with a health care provider or public-health official.

Pregnant people, people with weakened immune systems, and anyone caring for an infant younger than 12 months should seek prompt professional guidance after a possible exposure. Residents should rely on county health officials and medical providers for case-specific instructions.

Sources

• Maricopa County Department of Public Health: July 21 measles exposure notice
• CDC: Measles vaccine and post-exposure guidance
• Arizona's Family: Chase Field measles exposure report