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What is measles?

Measles is a disease that comes on quickly and spreads from person to person (viral). Measles can be dangerous, especially for babies, young children, and people with weak immune systems (the body system that fights off infection). A quarter of all measles patients must be treated in the hospital, and a few will die even with the best of care.

What are the symptoms of measles?

Symptoms include fever, runny nose, cough, not feeling hungry, “pink eye,” and a rash. The rash usually lasts 5–6 days. The rash begins at the hairline, moves to the face and upper neck, and then moves down the rest of the body.

How does measles spread?

Measles is spread from person to person through the air by droplets that contain the virus. It is highly contagious (easily passed from person to person).  If you and your child have been near someone with measles, then you have been exposed to the virus. Measles can easily pass from the infected person to other people starting 4 days before you see the rash until 4 days after the rash appears.

How long does it take to show signs of measles after being exposed?

After being exposed, it takes about 10–12 days to see the first symptom, which is usually fever.

The measles rash does not usually appear until about 14 days after being exposed. That’s 2–3 days after the fever begins. How soon the rash appears can vary in some people, anywhere from 7 to 21 days after being exposed.

What are possible health problems from measles?

Measles can be severe in people with weakened immune systems.  Many St. Jude patients have weak immune systems because of their diseases and treatments.

How is measles diagnosed?

Measles is diagnosed by looking at both the patient’s symptoms and a blood or throat test.

Can measles be prevented?

Yes. The MMR vaccine contains live strains of measles, mumps, and rubella viruses. But, the viruses are attenuated, which means they are not as strong as the wild virus so harmless to people with normal immune systems. Usually, the first dose of vaccine is given after the child’s first birthday.

St. Jude patients with weak immune systems cannot receive the MMR shot because of the live viruses in the vaccine. When all family members get the MMR shot, it helps provide a circle of protection around the patient.

What should be done if someone is exposed to the measles?

If you or your child is ill or have been exposed to measles, you should call your primary clinic before coming to the hospital. This will help avoid putting other people at risk for getting measles.

If the exposed person has not had the vaccine, getting the measles vaccine within 72 hours of being exposed might prevent the disease.

People with weakened immune systems should not get the vaccine. Family members should be vaccinated to create a circle of protection around the patient.


If you have questions about measles or the MMR vaccine, please talk to your child’s doctor or nurse.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

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