🚨 URGENT HEALTH ALERT: Sixth Measles Case of 2026 Confirmed in Maricopa County

MARICOPA COUNTY HEALTH ALERT NOTICE

Public Health Measles Surveillance Alert for Clinicians

📍 Public Exposure Sites

People who were at the following locations at the listed dates and times may have been exposed and should watch for symptoms. The measles virus can survive in the air for up to two hours; the listed exposure times include that extended period.

💉 Post-Exposure Prophylaxis (PEP)

In some situations, certain people exposed to measles may be eligible for post-exposure prophylaxis (PEP) to reduce their risk of becoming ill. This includes some children under 12 months, pregnant women, and individuals with compromised immune systems. Individuals should contact their clinician for guidance.

🩺 Recommendations for Physicians

1. Consider measles in the differential of unvaccinated individuals who present with fever and a rash. Adults who received only 1 MMR vaccine as a child are considered fully vaccinated but may have waning immunity, and measles should not be excluded.
2. Minimize exposures of patients and staff by utilizing the infection control guidance below.
3. Make sure that all patients and clinical staff are adequately vaccinated.
4. Immediately report suspect cases of measles to the Maricopa County Department of Public Health by calling (602) 506-3747

🔬 Measles Laboratory Testing

For suspect measles cases, call (602) 506-3747 to coordinate with MCDPH for confirmatory testing through Arizona State Public Health Laboratory (ASPHL).

Specimen Collection

Collect the following two specimens for polymerase chain reaction (PCR) testing through ASPHL:

• Urine collection
• Nasopharyngeal swab

⏰ Optimal Testing Window

Detection of measles RNA is most successful when specimens are collected on the first day of rash through the 3 days following onset of rash. Detection of measles RNA by rRT–PCR may be successful as late as 10–14 days after rash onset.

🩹 Clinical Presentation of Measles

Measles typically presents in adults and children as an acute viral illness characterized by a prodrome with high fever (>101 °F), cough, coryza, and conjunctivitis followed several days later by a generalized maculopapular rash.

Rash Characteristics

• Usually starts on the face (starting at the hairline)
• Proceeds down the body and may include the palms and soles
• Appears discrete but may become confluent
• Lasts several days
• Fades in the same order that it appears
• Koplik spots are occasionally seen

Symptom Timeline

Signs and symptoms typically appear 7 to 21 days after exposure. Symptoms may be mild, absent, or atypical in persons who had some degree of immunity to measles virus before infection (e.g., in previously vaccinated persons who had waning immunity or children aged > 1 year who passively acquired maternal antibodies).

Potential Complications

• Diarrhea
• Otitis media
• Pneumonia
• Hepatitis
• Encephalitis
• Subacute sclerosing panencephalitis (SSPE) — a serious brain infection that may not appear until years after the initial measles infection
• Death

🦠 Transmission

Measles is highly contagious. Approximately 90% of persons lacking immunity who are exposed to measles virus will develop the disease.

How Measles Spreads

• Transmitted by airborne particles or direct contact with respiratory secretions of an infected person
• Can live for up to 2 hours in an airspace where an infected person has coughed or sneezed
• Individuals with measles are infectious from 4 days before rash onset through 4 days after rash onset (9 days total)
• A person with measles can spread the virus to others before symptoms begin

🏥 Infection Control at Health Care Facilities

The following steps are recommended to prevent measles transmission in health care facilities:

Facility Preparation

• Post signage outside your facility and have surgical masks available.
• Do not allow suspect measles patients to remain in the waiting area or other common areas

Patient Isolation

• Immediately isolate them in an airborne isolation, negative pressure room — if available — otherwise, utilize a private room with a closed door
• If a potential measles patient is evaluated in a room that is not a negative pressure room, do not use that room for the next 2 hours
• Immediately place a surgical mask on the patient

Arrival Procedures

• When possible, ask the suspect measles patient or their guardian to call the facility when they arrive outside, so staff can meet them before they enter the facility
• When possible, have the suspect measles patient use an alternative entrance into the facility, like a back door, that will minimize exposure to other patients

🏥 Infection Control at Health Care Facilities

✅ Vaccination is the Most Effective Protection



Two doses of the MMR (measles, mumps, rubella) vaccine are 97% effective and recommended for all children. Unimmunized adults are recommended to receive at least one dose of MMR vaccine. Individuals born before 1957 or who had measles as a child are generally considered immune.

👶 Updated Guidance: Infants 6–11 Months

In alignment with CDC guidance and in the setting of a local measles outbreak in Maricopa County, MCDPH recommends infants aged 6–11 months receive early MMR vaccination in addition to the two scheduled doses at ages 1 year and 4–6 years.

Evidence of Immunity for Healthcare Professionals

Ensure your healthcare staff is fully immunized. Review immunity to measles for all healthcare workers, including ancillary staff such as office staff, dietary staff, housekeeping, maintenance, etc. — anyone that shares airspace in your facility with a patient.

Documentation Requirements

• Health care workers should have documented evidence of immunity to measles
• Healthcare workers should receive two doses of MMR, at least 28 days apart, regardless of year of birth, unless they have documentation of previous immunity

Important Facts About Measles

• Unvaccinated people have a 90% chance of becoming infected if exposed
• Vitamin A does not prevent measles
• In rare cases where a vaccinated person gets infected, their illness will be less severe than if unvaccinated
• There is no treatment for measles — only supportive care
• There is no treatment to relieve symptoms or shorten the duration of infection
• Infected individuals can spread measles to others before symptoms develop, while they still feel normal
• Long-term complications can include subacute sclerosing panencephalitis (SSPE), a brain infection that may not appear until years after initial infection