Measles

Last content update: 05/29/25

Healthcare providers are required to immediately report suspected or confirmed cases of measles to the Public Health Department. Call Public Health immediately, while the patient is still in your office, at (408) 885-4214 and select option 3. After hours, call (408) 998-3438 and ask for the Health Officer on call. Call, do not fax.

There has been an increase in measles cases in the United States in 2025, with outbreaks occurring in multiple states. While no outbreaks have occurred in California this year, several measles cases have been reported. Everyone who is not fully vaccinated against measles should get the vaccine, which is safe and highly effective.

Due to the recent cases, health care providers should be on alert for patients who have: (1) febrile rash illness and symptoms consistent with measles, and (2) travelled internationally, especially to countries with ongoing measles outbreaks or travelled domestically to areas experiencing measles outbreaks. Infected people are contagious from 4 days before the rash starts through 4 days afterwards.

For information on measles cases reported in California in 2025, refer to the California Department of Public Health’s Measles webpage.

When to suspect measles

Healthcare providers should consider measles in patients with:

Clinical symptoms consistent with measles including fever, rash, and any of the “3 Cs” – cough, coryza (runny nose), or conjunctivitis.
Epidemiological risk for measles including any of the following:
- International travel such as travel outside of North America, transit through U.S. international airports, or interaction with international visitors (including at U.S. tourist attractions) in the last 21 days.
- Domestic travel to an area with known measles transmission in the last 21 days.
- Known exposure to measles.

Ask about measles vaccination status, onset and duration of fever and rash, exposure to other persons with febrile rash illness, travel history, and contact with international visitors or visitors from areas with recent measles outbreaks in the three weeks prior to illness. When suspecting measles in your patient, immediately mask and isolate the patient per airborne precautions. Infected people are contagious from 4 days before rash onset through 4 days after rash onset.

Recommendations for suspected cases of measles

Mask and Isolate: Mask and isolate the patient immediately. Do not allow patients with suspected measles to remain in the waiting room or other common areas of the healthcare facility. Isolate patients in a single-patient airborne infection isolation room (AIIR) if available, or in a private room with a closed door until an AIIR is available.
1. Healthcare providers should be adequately vaccinated against measles and should adhere to standard and airborne precautions when evaluating suspect cases regardless of their vaccination status. All healthcare personnel entering the patient room, regardless of immune status, should use respiratory protection at least as effective as an N95 respirator per Cal/OSHA requirements.
Notify: Healthcare providers are required to immediately notify the Public Health Department of any suspected case of measles to ensure rapid testing and investigation. Call Public Health immediately, while the patient is still in your office, at (408) 885-4214 and select option 3. After hours, call (408) 998-3438 and ask for the Health Officer on call. Call, do not fax.
1. Be prepared to provide (1) a detailed description of fever and rash onset and evolution, (2) a photo of the rash, and (3) complete vaccination and travel history.
Test: If advised to test for measles by Public Health, collect a throat swab and urine sample for reverse transcription polymerase chain reaction (RT-PCR). Collect specimens in-office rather than sending the patient to a laboratory.
1. Throat swab: Use a sterile synthetic swab. Place swab into viral or universal transport media.
2. Urine sample: Collect 10-50 mL urine in a sterile container.
3. Storage and transport: Store all specimens at 4°C. Transport all specimens on cold pack within 24 to 72 hours. Specimens should be dropped off at the Public Health Laboratory along with a submission form.
Manage: If discharged home: provide patient suspected to have measles with instructions to isolate at home until test results return. If transferred to a higher level of medical care: directly inform EMS and the accepting facility so that appropriate precautions can be put in place. In coordination with the Public Health Department, provide appropriate measles post-exposure prophylaxis (PEP) to close contacts without evidence of immunity, either MMR or immunoglobulin.

Vaccination

Measles can be prevented with measles-containing vaccine, which is primarily administered as the combination measles-mumps-rubella (MMR) vaccine. One dose of MMR vaccine is approximately 93 percent effective at preventing measles; two doses are approximately 97 percent effective.

The MMR vaccine is included in the routine childhood immunization schedule. CDC recommends children get two doses of MMR vaccine, starting with the first dose at 12 to 15 months of age, and the second dose at 4 to 6 years of age. Teens and adults should also be up to date on their MMR vaccination. There are also travel-related vaccine recommendations for people who are traveling internationally or to outbreak-affected areas in the United States.

For more information on the MMR vaccine, refer to the CDC’s Measles, Mumps, and Rubella (MMR) Vaccination: Information for Healthcare Providers webpage.

Measles and international travel

Measles cases often originate from unvaccinated or undervaccinated U.S. residents who travel internationally and then transmit the disease to people who are not vaccinated against measles. All international travelers over the age of 6 months should be vaccinated against measles before traveling.

Before traveling abroad:

Infants 6 to 11 months old need 1 dose of MMR vaccine
Children 12 months and older need 2 doses of MMR vaccine
Adults born during or after 1957 without evidence of immunity against measles need documentation of two doses of MMR vaccine at least 28 days apart

After traveling abroad:

Patients should monitor for fever and rash for 3 weeks after international travel

Measles and domestic travel

There have been multiple confirmed measles cases and outbreaks reported across the United States in 2025. Any person traveling to outbreak-affected areas should follow all vaccination recommendations issued by state, local, tribal, or territorial health departments. Healthcare providers can find updated outbreak-related recommendations issued by state or local health departments on the CDC’s Measles Cases and Outbreaks webpage.