Measles Situation Update

As of September 17, 2026, 3,471 confirmed measles cases have been reported to the US Centers of Disease Control and Prevention by 47 jurisdictions; 93% of these cases were unvaccinated. There have been 39 new outbreaks (defined as 3 or more related cases) reported in 2026, and 95% of confirmed cases are outbreak-associated.

As of September 21, 2026, 59 confirmed measles cases, 92% unvaccinated, have been reported in California this year.

CDPH notified the public of a measles exposure across multiple counties involving a train and bus passenger on September 18, 2026.  Alameda County Public Health Department notified the public of the same measles exposure on September 22, 2026.  Persons who traveled on Amtrak train #749 that departed from Sacramento at 6:53 p.m. on September 13, 2026 through 9:40 p.m., and Amtrak train #6 that departed from Emeryville at 8:25 a.m. on September 14, 2026 through 8:00 p.m. on September 15, 2026 may have been exposed to measles.

All persons who were traveling on these trains during the times and dates indicated should watch for symptoms of measles which can appear in seven to 21 days (9/20/26 – 10/5/26) after the exposure. Those symptoms include fever, cough, runny nose, red eyes, and a rash that can last up to a week. Some people may develop complications such as diarrhea, middle ear infection, and pneumonia (lung infection). One in 1000 people with measles may develop encephalitis (brain infection) and one to two children of every 1000 people with measles may die from lung or brain complications.

If you were traveling on either of these trains during the times listed and if you or your child(ren) are:

  • An infant 11 months of age or younger
  • Not vaccinated for measles
  • Unsure of your measles vaccination status
  • Pregnant
  • Immunocompromised (having a weakened immune system)
  • A health care worker
  • A childcare provider

Please call your health care provider and your local health department; residents outside of California may call their state health department. If you are a resident of Alameda County, call (510) 267-3250.

Plan for Travel

Measles is still common in other countries! Two doses of MMR vaccine are recommended for all international travelers over 12 months of age at least 2 weeks before planned travel; infants 6-11 months can receive one dose before travel.

Please see Plan for Travel – Measles (CDC) for more information or watch this video.

Call your doctor or find travel clinics that serve uninsured or underinsured community members on our Immunization Clinics list.

About Measles

Measles, also called rubeola, is a highly contagious illness caused by a virus. People usually do not show signs of measles until 7-14 days after being exposed to someone with measles. Measles can seem like a cold the first few days with a fever (103-105°), cough, sore throat, red watery eyes, and runny nose. About 2-4 days later a red blotchy rash appears that can last from 5-7 days. The rash starts on the face and neck and moves down the body.

Measles is spread person-to-person when an infected person coughs, sneezes, or shares food or drinks. The virus travels easily through the air. It can live in the air and on surfaces for up to two hours. An infected person can pass the virus during the four days before the rash appears and for four days after the rash begins. A person who is exposed to measles and is not protected by immunization may become sick 7 to 21 days after exposure.

Who is at risk for serious illness from measles?

  • Children younger than 5 years of age
  • Adults older than 20 years of age
  • Pregnant people
  • People with weakened immune systems, such as from leukemia or HIV infection
  • Unvaccinated people have a very high likelihood of contracting measles if exposed.

Some people may suffer from severe complications, such as pneumonia (infection of the lungs) and encephalitis (swelling of the brain). They may need to be hospitalized and could die. Measles illness during pregnancy can cause early labor, miscarriage, and low birth weight infants.

Measles is prevented through vaccination.

Prevention

Measles/Mumps/Rubella (MMR) Vaccine

Before there was a vaccine, it is estimated that there were over 3 million measles cases every year in the US, and 500 deaths due to measles. The MMR is highly effective. Measles vaccination protects not just the person being vaccinated, but the community around them, including babies less than 12 months old, who are too young to be vaccinated. Two doses of MMR vaccine are more than 97% effective at preventing measles.

Who should get vaccinated?

  • The CDC recommends two doses of MMR vaccine for children, the first at 12-15 months and the second at 4-6 years old. Vaccine schedules (CDC). English | Spanish
  • MMR recommendations if planning international travel can be found here.
  • Adults born after 1956 without evidence of immunity should receive at least one dose of MMR vaccine.
    • Two doses are recommended for adults who plan to travel internationally and to attend many colleges.
    • Two doses are also advised if you work with babies, children, pregnant women, or people with weak immune systems.

How safe is the measles vaccine?

The measles vaccine is very safe. The most common side effects are soreness where the shot was given and fever. Sometimes there is a mild rash or swollen glands in the cheeks or neck.

Where do I go to receive a vaccine?

The best place to receive an MMR vaccine is at your doctor’s office, but there are also other options such as local clinics. Any time you receive a vaccine, be sure to keep your record. If you are unsure of your vaccine history, here are some tips.

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