Measles
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The measles-mumps-rubella (MMR) vaccine is effective. Two doses provide 97% protection against measles.āÆ
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Measles is very contagious. Measles spreads when someone infected speaks, coughs, sneezes or breathes. It can linger in the air up to two hours after the infected person has left.āÆāÆ
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Unvaccinated people are at high risk. Roughly 90% of those unvaccinated and exposed to measles will contract the disease.āÆāā
Measles Activity in California, 2025
As of April 21, 2025, nine confirmed measles cases have been reported. The affected jurisdictions are:
- Fresno
- Los Angeles
- Orange
- Placer
- Riverside
- San Mateoā
- Tuolumne ā
āJanuary 2025ā
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ā0
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āāFebruary 2025
|
ā3
|
āāMarch 2025
|
ā6
|
April 2025ā
|
ā0
|
These data are provisional and subject to change.āÆ CDPH will update this page every Tuesday.
What is Measles?
Measles is a contagious viral disease. Itās widespread in many parts of the world, including Europe, Africa and Asia. While measles is eradicated in the U.S., cases around the country and world remind us how important vaccines are.
The measles-mumps-rubella (MMR) vaccine provides the best protection against disease and serious illness. Most measles cases in the U.S. result from international travel. Itās important that you and your family are up to date on all vaccines before traveling abroad.
Measles begins with a fever that lasts a couple of days. Itās followed by:
- āA cough
- Runny nose
- Conjunctivitis (pink eye)
- Rash
The rash usually appears on the face, along the hairline and behind the ears. Then it affects the rest of the body. Those infected can spread measles about four days before their rash starts to four days afterwards. āā
How Do I Protect Myself?
MMR vaccines are our best defense against the disease and its complications.
CDC recommends two doses of MMR (measles, mumps, rubella) vaccine for:
- Children: one dose at 12 months of age and another at 4ā6 years.
- Older children, adolescents and adults without documented doses of MMR vaccine.
āTalk to your health care provider or visit
MyTurn.ca.govā to make a vaccine appointment.ā
Unsure if youāre vaccinated against measles? Check your
CA Digital Vaccine Record (DVR) or ask your healthcare provider. If no records exist, get vaccinated.ā
Whatās Recommended for International Travel?
Whether youāre visiting family or exploring the world, plan to receive the MMR vaccine. It takes your bodytwo to threeā weeks to get the most protection against measles after vaccination.
Before international travel:
- Babies 6ā11 months of age should receive one dose of MMR vaccine.
- Ensure everyone 12 months and older are up to date with two doses of MMR vaccine. If theyāre not up to date, they should get two doses at least 28 days apart.
Why is Vaccination Important?
Measles can be very serious, especially in unvaccinated young children and pregnant people. Measles can cause:
- Pneumonia
- Encephalitis (brain swelling)
- Hospitalization
- Sometimes death ā
Usually, high levels of immunity in the general population limit measles outbreaks. However, measles does spread in communities with lower coverage.
Recent Measles Cases in Californiaāā
- In 2024, 15 cases were confirmed
- In 2023, four cases were confirmed
Please see data section for counts in previous yearsā.
Measles Outbreaks in California
āIn 2019, there were 73 confirmed measles cases in California. This included 41 cases linked to six outbreaks; defined as three or more cases. Of the six outbreaks, five were linked to patients with international travel. One had an unknown source. The largest outbreak had 21 cases and occurred in a health care setting. The other five outbreaks involved from three to five cases.ā
From December 2014āApril 2015, roughly 131 Californians got infected from an outbreak in Disneyland. The outbreak also infected residents of six other states, Mexico and Canada.
For information on measles cases and outbreaks nationwide, please see the CDC Measles Cases and Outbreaks.āāā