Measles in California

Situation

As of January 23, 2026, the Centers for Disease Control and Prevention (CDC) reports 2,255 confirmed measles cases in the U.S. for the year 2025, the highest annual total since measles was declared eliminated in 2000, and 416 confirmed cases in 2026 to date.

National outbreaks have been reported across multiple states, with significant activity in the Southeast and Southwest. The California Department of Public Health (CDPH) confirmed that 25 measles cases were reported during 2025, including cases in multiple Bay Area counties, and a total of 2 confirmed cases in 2026 have been identified in San Mateo and Napa counties. CDC and CPDH continue to update case counts weekly and maintain guidance on surveillance and response. 

Background 

Measles is extremely contagious. Symptom onset begins with fever, cough, coryza (runny nose), and conjunctivitis (pink eye), followed by a rash 2–4 days later starting on the face and spreading downward on the body. Infected individuals are contagious from 4 days before the rash appears and remain infectious 4 days thereafter. The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Droplets can remain infectious in the air and on surfaces for up to 2 hours after an infected person leaves an area.

Patients with prodromal symptoms can be very ill and often visit healthcare facilities at least 2–3 times before rash onset. A self-reported history of measles immunization or infection does not rule out the possibility of measles. Clinicians should confirm vaccination status. All staff should be fully vaccinated. 

Preparing Your Facility for The Possibility of Measles 

1. Confirm immunity of contacts and healthcare staff with unknown vaccination status by ordering Measles IgG only.
   1. Do not order measles IgM testing for asymptomatic individuals as there is a substantial possibility of a false positive IgM result.
   2. Confirming staff immunity now can help to avoid staff exclusion from work in the event of an exposure.
   3. CDC recommends 2 doses of MMR for healthcare workers without evidence of immunity.
2. Sick-waiting rooms:
   1. If possible, set up a sick-waiting room with clear signage at entrances and exits that direct patients with fever and rash to notify staff of their symptoms.
      1. Train staff to immediately implement airborne precautions if measles is suspected.
      2. Mask and isolate the patient in an airborne isolation room.
      3. Do not re-use the exam room for two hours after the patient has left the room.
      4. If referring the patient to other healthcare facilities, ensure that airborne precautions are in place.
      5. Only staff immune to measles should be taking care of suspected measles cases. Staff should use N-95 respirators.
      6. For more complete infection control guidance in healthcare settings, refer to the CDPH Measles Exposure Quicksheet.
3. The measles-mumps-rubella (MMR) vaccine is Two doses provide 97% protection against measles. Educate and advocate for MMR vaccination for unvaccinated children and adults including booster for those who have not completed the MMR vaccine series, in accordance with the American Academy of Pediatrics (AAP) Vaccine Schedule.

Guidance For Suspected Measles at Your Office

1. Consider/suspect measles in patients with fever, including subjective (tactile), and/or a maculopapular rash that starts on the head and Patients with measles typically have a high fever (≥101°F or 38.3°C).
2. If you have a patient suspected of measles at your clinic, keep the patient in a quarantined exam room under airborne precautions, and immediately call Sonoma County Disease Control Program at 707-565-4568. After 5:00pm or weekends, call Sonoma County Dispatch at 707-568-5992.
   1. Patients calling the clinic with complaint of rash and fever should be instructed to call the desk when they arrive outside the clinic and before entering the building.
3. Plan to order a measles test through the Sonoma County Public Health Laboratory and collect specimens while the patient is still at your facility, which will include the following:
   1. Throat/Oropharyngeal (OP) Swab:
      1. Using sterile synthetic swab (e.g. Dacron)
      2. Vigorously and carefully swab tonsillar areas
      3. Place swab into liquid viral or universal transport media
      4. Do not use bacterial transport media
   2. Urine sample for PCR testing:
      1. Collect 10-50ml of urine in a sterile urine specimen container
      2. Collect urine at the beginning of the The first morning void is ideal.
4. Hold all specimens for testing by Sonoma County Public Health Laboratory for expedited analysis and results.
   1. Sonoma County can support with transport of the specimen from your office to the Public Health Laboratory.
5. Assess patient for history of:
   1. Measles vaccination status
   2. Exposure to a known measles case
   3. Travel history up to three weeks prior to symptoms
      1. Travel to North America and areas with measles cases or outbreaks
      2. History of transit through S. and international airport
      3. History of interaction with foreign visitors
      4. History of visiting popular S. tourist attractions including theme parks
6. Advise patients with suspected measles to stay home and avoid visitors until at least four days after rash appears and/or until cleared by the Sonoma County Disease Control Program.
7. Patients with suspected measles should go home by private vehicle and should only be accompanied by someone immune to They should NOT use public transportation or ride-sharing services (e.g. Uber, Lyft).

For supportive treatment of diagnosed measles cases and clinical management, refer to the CDC Clinical Overview of Measles.