3rd measles case reported in Pima County as officials caution about potential outbreak

A third person in Pima County has been confirmed as being infected with measles, health officials said Tuesday, saying they “remain on high alert” and telling people who were at three specific locations in Tucson last week to monitor for symptoms. 

Vaccination is the best defense against a potentially deadly measles case, officials said.

People who were at the El Rio Health Northwest Clinic, 320 W. Prince Rd., on last Wednesday and Thursday (8 a.m.-6 p.m. both days) should be especially aware of the need to monitor for symptoms, officials said. Exposures may also have occurred at the Fry’s at 2001 E. Irvington Rd. last Wednesday (5-8 p.m.) and El Herradero market, 2770 W. Valencia Rd., last Thursday (5-8 p.m.)

The case announced Tuesday afternoon is an adult Tucson resident who “was not fully vaccinated and developed symptoms following direct exposure to a previously reported measles case,” Pima County Health Department officials said. The third person “is not hospitalized and is isolating and recovering at home.”

The second case was announced Friday, Jan. 16. That individual, who contracted the infection while traveling outside the U.S., is not connected to a case announced on January 1. The first recent measles case here was diagnosed in a migrant who was detained by Border Patrol agents, a government official with knowledge of the situation but who isn’t authorized to provide that information to the press told the Sentinel. That case involved Santa Cruz County health officials as well as Pima officials, and the infected person was hospitalized in Tucson.

Measles is a highly contagious virus — it has what is referred to as an R-naught of 12 to 18, according to Dr. Theresa Cullen, PCHD director, meaning that “out of every 20 people that may come in contact with an acute case of measles, 18 may acquire the disease.”

It can cause permanent hearing problems or vision loss, pneumonia, brain damage or even death, and is especially risky for children under age five.

The virus can can spread through direct contact, infected surfaces and live in the air for up to two hours.

Symptoms can appear 7-14 days after exposure, and those carrying the virus can begin spreading even before that time — up to 4 days before a rash appears.

People who were at any of the three locations (El Rio Northwest, Fry’s on Irvington, El Herradero) on those days and hours last week should monitor themselves through Feb. 12, officials said.

“PCHD is conducting a comprehensive public health investigation to identify and notify individuals who may have been exposed. State, regional and local public health and healthcare partners remain on high alert and in close coordination,” they said.

Two weeks ago, officials said that “the overall risk to the general public remains low,” but dropped that language from their public announcement Tuesday.

As part of contact tracing efforts, PCHD will be contacting individuals who may have been exposed, they said. Residents are asked to answer phone calls and respond promptly to public health outreach to support these efforts. Calls from PCHD will come from a 520-724-XXXX phone number.

The earlier case sparked officials to caution people to monitor for symptoms if they were at El Rio Northwest on Jan. 13 from 11:30 a.m. to 3:30 p.m., or the El Rio clinic at 839 W. Congress St. on Jan. 14 from 11 a.m. to 7 p.m.

“There are ways to protect yourself and your family from acquiring
measles,” Cullen said at the beginning of the month. “The best way to do that, obviously, is to ensure
that you are appropriately and adequately vaccinated.

Symptoms

Symptoms can begin about 14 days after being exposed and can include a high fever (104°F to 105.8°F), a full-body rash that usually starts a few days after the fever, cough, runny nose, diarrhea and red, watery eyes.

Serious complications can include permanent hearing problems or vision loss, pneumonia, brain damage and death.

Symptom monitoring

Anyone who believes they may have been exposed to measles and is experiencing symptoms should:

• Stay home and avoid contact with others
• Contact a healthcare provider or PCHD (520-724-7797) before seeking in-person care
• Follow public health guidance to prevent further spread

 Vaccination

“While no vaccine provides 100% protection, two doses of the MMR vaccine offer very strong immunity,” said Cullen. “Because immune responses can vary from person to person, high community vaccination coverage is essential to protect those who are most vulnerable and to limit the spread of measles.”

One dose of the MMR (measles, mumps, rubella) vaccine is about 93% effective, officials said. Two doses are about 97% effective.

Individuals born before 1957 are generally considered immune due to likely prior exposure, while other people who are unvaccinated or under-vaccinated are at higher risk of infection

MMR vaccinations are available at all Pima County Health Department clinics, regardless of insurance status. The vaccine is also available at many commercial pharmacies, primary care providers and federally qualified health centers.

For more information about measles and where to get vaccinated, visit pima.gov/measles or contact PCHD Epidemiology at 520-724-7797.

Pima health officials have cautioned resident to “be aware of myths about measles,” noting that “vitamin A does not protect against measles infections” and “there is no link between the MMR vaccine and autism.”

Cullen said at the beginning of January that local schools show a vaccination rate of 95 percent and had reached “herd immunity.”

“We
obviously have some schools in some areas where we’re not seeing that,
but I do think it is a tribute to Pima County and our vaccination rates
related to measles that this is our first case,” Cullen said.

She said the state of Arizona had seen 205 measles cases in 2025.

“What
we know is in areas of the state where there are lower immunization
rates, there have been significant outbreaks,” Cullen said. “So what we
want is to just encourage people to continue to follow what they’ve been
doing with measles.”

The last measles outbreak in Pima County was
in 2008, when an infected person spread the disease to 16 other people,
Cullen said. The last known case was in 2019, when an international
traveler tested positive for the disease.

Pima officials have noted that a “natural infection” of measles carries higher risks than getting vaccinated. In recent outbreaks, about 99% of people infected weren’t immunized and almost 20% of infected children had to be hospitalized. 

“If you’re unsure of your vaccination status, talk to your doctor. It is not harmful to get an extra dose,” they said.