What is Measles?Updated 7-11-2024
  • Measles is a serious respiratory disease caused by an airborne virus.
  • Measles is one of the world’s most contagious diseases.
  • One infected person can spread the disease to 9 out of 10 unvaccinated persons who come into close contact with the infected person.
  • Measles can be prevented by the measles-mumps-rubella (MMR) vaccine.
Measles FAQ Flyer

Fact Sheet

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Measles: Symptoms and Complications

Common symptoms for measles include:

  • High fever (higher than 101° F)
  • Cough
  • Runny nose
  • Red and watery eyes
  • Tiny white spots (Koplik spots) that may appear inside the mouth 2-3 days after symptoms begin.
  • Rash 3-5 days after other signs of illness. The “measles rash” typically starts at the face and then spreads down to the rest of the body.

Measles can cause several health complications. Common complications include ear infections and diarrhea. About 1 in 5 people who are not vaccinated in the United States who get measles will be hospitalized. Serious complications include lung infection (pneumonia), dehydration, or swelling of the brain. Before widespread vaccines in the United States, hundreds of people died from measles.

Those who are more likely to have serious complications due to measles are:

  • Children younger than 5 years of age
  • Pregnant people
  • People with weakened immune systems
How does Measles Spread?
  • The virus spreads easily through the air when an infected person breathes, talks, coughs, or sneezes.
  • The virus can stay in the air and on surfaces for many hours, even after the infected person has left.
  • The infected person can spread the disease before they have any symptoms. This could be up to four days before a measles rash appears and up to four days after the rash appears.

If you think you or your someone in your family may have measles because you or they have symptoms , have not been vaccinated against measles, and/or have been traveling:

  • Stay home and call your doctor and let them know of your concerns.
  • Stay away from other individuals or large groups in places such as school, daycare, and waiting rooms, before speaking to your doctor.
  • If you are a health care provider whose patients have symptoms compatible with this disease, call LACDPH immediately.

If you think you have been exposed to measles:

  • Call your doctor immediately to let them know you have been exposed to someone with measles.
  • Your doctor may be able to determine if you have protection against measles based on your vaccine record or previous lab results.
  • Your doctor may also make special arrangements to evaluate you to limit risk to other patients and staff.
  • Make sure to wear a facemask that covers your nose and mouth.
  • Stay away from places where there are large groups of people who are at higher risk of getting sick, such as schools, hospitals, or childcare. Do not return until your doctor says it is okay to return. This will help make sure that you do not spread measles to others.
Information for the Public
MMR Vaccine

Making sure everyone gets 2 doses of the measles-mumps-rubella (MMR) vaccine is the best way to protect yourself, your family, and community against measles. The MMR vaccine is safe and works very well in preventing measles. Two doses are 97% effective, and one dose is 93% effective in preventing measles. The spread of measles can be prevented if at least 95% of community members have received 2 doses of the MMR vaccine.

Most individuals born or attending school in the United States get vaccinated when they are children. They receive their first dose at 12-15 months of age and their second dose at 4-6 years of age. If you are an adult who is travelling internationally, you should get vaccinated against measles if you did not receive 2 doses as a child.

Learn more about who should get the MMR vaccine.

Where to get the Vaccine

There are many places to get the MMR vaccine. If you have insurance, talk to your doctor or check with your local pharmacy to see what vaccines are offered. Most health insurances cover the cost of all recommended vaccines for children and adults.

If you are uninsured or underinsured, there are programs available to help cover the cost of vaccines. Children who are 18 years of age or younger are eligible to receive vaccines at no cost through the Vaccines for Children (VFC) Program if they are:

  • Eligible for or are enrolled in Medi-Cal
  • American Indian or Alaskan Native
  • Uninsured (do not have health insurance)
  • Underinsured (private health insurance does not cover the full cost of vaccines)

Click to see if your child is eligible to receive VFC vaccines: English | Spanish

Uninsured or underinsured adults can access free or low cost vaccines at select clinics enrolled in the Vaccines for Adults (VFA) program. For more information on who is eligible, read VFA Eligibility Based on Insurance Status. You can use the following resources for more information on locating clinics:

You can also dial 2-1-1 for a list of free or low cost vaccine clinics. This includes Vaccines for Children (VFC) provider locations that serve Medi-Cal eligible children and uninsured or underinsured adults. Learn more about specific vaccine information for different age groups:

Keeping Record of Your Immunization Records

Are you not sure if you have been vaccinated against measles or you can’t find your vaccine records?

If you need official copies of your vaccine records, or if you need to update your personal records:

Additional Resources
Signage and Flyers (LACDPH)
For Parents: Addressing Concerns about Measles Vaccination
Exposure Notification Flyer
A Measles Reference for Schools and Child Cares
FAQ: Receiving A Health Officer Order During a Measles Outbreak
Information for Providers
When to Suspect Measles
  • Consider measles in any patient with a febrile rash and clinically compatible symptoms (see below), especially if they are unvaccinated or under-vaccinated or have any of the following risk factors in the past 4 weeks:
    • Travel, especially international or domestic through an international airport.
    • Contact with someone with a febrile rash illness.
    • Exposure to a known or possible measles case.
Clinical Presentation
  • Immunocompetent patients with measles typically exhibit high fever, with one or more of the “3 C’s” conjunctivitis, coryza (runny nose), and cough. Patients may have erythematous, white or grey specks on the buccal mucosa, commonly referred to as Koplik spots, prior to the onset of rash.
  • Two to 4 days after initial symptoms, measles rash usually begins along face and hairline and spreads downwards to trunk. Patients are typically infectious 4 days prior to onset of rash to 4 days after rash.
Isolation of Suspected Cases
  • Patients with signs or symptoms of measles should be rapidly identified and isolated from other patients prior to or as soon as possible after entry into the facility.
  • If possible, screen patients prior to their arrival at the healthcare setting. Patients with a febrile rash and clinically compatible measles symptoms who are unimmunized or who have had international travel or other potential exposures to measles should be evaluated before clinic opens or after it has closed, to avoid exposing other patients.
  • Patients with suspected measles should wear a well-fitted medical mask or respirator and be placed in an airborne infection isolation room if one is available. If this cannot take place, escort masked patient away from other patients directly to a private room for evaluation and specimen collection. Do not use this room again until 2 hours after the patient has departed the room.
  • If a private room is not available, evaluation and specimen collection can be considered outside the health center, e.g., in patient’s car.
  • Do not wait for laboratory confirmation, report immediately by telephone for both confirmed and suspected cases upon suspicion of measles. Public Health will guide you through the collection of specimens for testing and management of the patient under investigation as well as asymptomatic contacts for suspected or confirmed cases. Consultation is required before sending specimens to the Public Health Laboratory:
    • Weekdays 7:30 am – 5:00 pm: Call 213-351-7800 - Epidemiologist on Duty
    • Non-business hours/weekends: Call 213-974-1234 - Administrative Officer on Duty
Diagnostic Testing
Vaccine Recommendations
MMR Vaccines Number of Doses Age Recommended Age Dose & Route
1st Dose 2nd Dose M-M-R- II PRIORIX

2* 12-15 months
4-6 years
and/or at least 4 weeks after 1st dose
12 months* 0.5 mL Subcutaneous (SQ)
Intramuscular (IM)
0.5 mL SQ
> 19 years At least 4 weeks after the 1st dose
Preferred injection site in small children is the anterolateral aspect of the thigh
ProQuad® 1
MMR & Varicella
2* 12-47 months 4-6 years
or at least 3 months after the 1st dose
12 months
12 years
IM or SQ
The posterior triceps aspect of the upper arm is the preferred site for older children and adolescents
MMR (M-M-R II and PRIORIX) are fully interchangeable for all indications for which MMR vaccination is recommended.
MMRV (ProQuad) vaccine is only licensed for use in children 12 months through 12 years of age.
MMRV (ProQuad) may be given at the same time as other vaccines.
1 Associated with a higher risk for fever and febrile seizures in children 12-23 months of age
*An additional dose may be indicated in outbreak situations and foreign travel where measles exposure is likely.
Doses given before 12 months are invalid. May receive 1st dose of MMR 4 days before 1st birthday
*Pregnancy is a contraindication to vaccination with live virus vaccines, including MMR and vaccines. ACIP recommends that pregnancy be avoided for 1 month following receipt of MMR vaccine.
Post Exposure Prophylaxis
  • Individuals who are exposed to measles and do not have evidence of immunity should be offered post-exposure prophylaxis to protect them and modify the clinical course of disease.
  • If eligible and no contraindications, patients should receive MMR or MMRV vaccine within 72 hours of initial measles exposure, or immunoglobulin (IG) within 6 days of exposure.
  • Do not administer measles containing vaccine and IG simultaneously, as immunoglobulins can interfere with vaccine effectiveness.
  • Treatment is supportive.
  • The WHO recommends vitamin A for all children with acute measles, regardless of their country of residence, to reduce the risk of complications.

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  • Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

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