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Public Health - Seattle & King County

Measles facts

What is it?

  • Measles is a disease with fever and rash that can be serious.
  • It is caused by the measles virus and spreads easily from person to person.
  • People at high risk for measles include:
    • Persons who have not been vaccinated against measles.
    • Infants less than 1 year of age (before they are vaccinated against measles.)
    • Pregnant women who have never had measles or the measles vaccine.
    • Persons with weakened immune systems.
    • Persons who were vaccinated with a type of vaccine that was available from 1963-1967 and have not been re-vaccinated.
  • People born before 1957 are generally considered immune (protected) because they probably had measles when they were young.

What are the symptoms?

  • Symptoms start about 7–21 days after being exposed to the virus, and the illness lasts from 1 to 2 weeks.
  • Measles starts with a runny nose, watery eyes, cough, and high fever.
  • After 2 to 4 days, a raised, red rash appears, typically starting on the face and spreading down the body and then to the arms and legs. The rash usually lasts 4 to 7 days.
  • People with measles are contagious for 4 days before until about 4 days after the rash begins.
  • People with measles can also develop ear infections, pneumonia, or inflammation of the brain (encephalitis). Measles can cause miscarriages or premature delivery in pregnant women.
  • Rarely, people can have mild cases of measles that are not recognized as measles infections.

How is it spread?

  • The virus is in the mucus in the nose or throat of a person with measles.
  • Measles spreads easily through the air when an infected person sneezes or coughs. The droplets can get into other people's noses or throats when they breathe or put their fingers in their mouth or nose after touching an infected surface.
  • A person with measles can spread the virus onto objects that have been sneezed or coughed on and the virus can live in the air for up to 2 hours.

How is measles diagnosed and treated?

  • Measles is diagnosed from a blood test, testing a swab of the inside of the nose and testing the urine for the virus. Usually all these tests are done at one time.
  • There is no specific treatment for measles. Rest and drinking plenty of fluids are recommended. Because a virus causes measles, antibiotics are not useful.
  • If complications develop (like pneumonia) additional treatment may be needed.

How is measles prevented?

  • Measles can be prevented through vaccination with the MMR vaccine. It combines measles vaccine with the vaccines for mumps and rubella.
  • In Washington State, all children are required to have MMR vaccination for entry into a school or childcare center.
  • People who have measles should avoid contact with others and avoid public places until at least 4 full days have passed since the time the rash appeared.
  • People who have been exposed to measles or think they may have measles should stay home, avoid public places, and consult their health care provider immediately. Be sure to call ahead before visiting your health care provider to avoid spreading measles to other people in the waiting room.
  • Measles vaccine given within three days of exposure can help prevent infection in healthy non-pregnant persons.
  • Immune globulin is a medication that can be used within 6 days of exposure to protect people at high risk for complications from measles including pregnant women, infants and people with weakened immune systems.

Report all King County cases to Public Health by calling 206-296-4774.

For King County health care providers: