Measles FAQ: Symptoms, Prevention, and More

Medically Reviewed by Renee A. Alli, MD on June 06, 2021

What is measles?

Measles is a respiratory disease caused by a virus. It can have life-threatening complications. The CDC calls it the "most deadly of all childhood rash/fever illnesses."

It spreads easily, but the measles-mumps-rubella (MMR) vaccine can prevent it. The CDC recommends that all children, and some adults, get the MMR vaccine.

The U.S. declared measles eliminated from the nation in 2000, but there have been outbreaks since then, and it's still common in other countries.

What are the first symptoms, and how quickly do they usually show up?

People usually get a fever, cough, runny nose, and red eyes first. Within a few days, a red rash starts on the face and can spread to the rest of the body. If you notice those signs, tell your doctor right away.

What are the possible complications?

Diarrhea and ear infections, which may lead to hearing loss, can happen as a result of measles.

Pneumonia and brain swelling are other potential complications. About 1 or 2 of every 1,000 children with measles dies of it, the CDC estimates.

How is measles spread, and how easily?

You can catch measles from anyone who has measles. If you're not immune, you're very likely to get it if you're around someone who has it, because the virus spreads so easily.

Just a cough or sneeze from an infected person launches the measles virus into the air, where you can breathe it in. People can spread it 4 days before they first get the measles rash, and for 4 days after the rash starts. The virus can live for up to 2 hours on a surface or in the air. You can get it if you touch an infected surface and then touch your mouth, nose, or eyes.

Measles is so contagious that 90% of people who aren't immune will get the disease if they're close to someone who has it.

How do you prevent measles?

It's simple: Get vaccinated.

You get two doses of the MMR vaccine. Children usually get the first dose when they are 12 months old, and a second before kindergarten. However, if the child is under 12 months old and is traveling to an area where measles is common, a first dose may be given at 9 months of age and a second at 12 months.  

On its website, the CDC calls the vaccine "very effective" and states that "one dose is about 93% effective at preventing measles and two doses about 97% effective."

Before the vaccination program started, 3-4 million people per year in the U.S. got measles, and 400-500 of them died, the CDC estimates.

Do adults need the MMR vaccine?

If you got two doses as a child, you're covered for life. You don't need a booster shot.

If you weren't vaccinated, you may need it. "Generally, anyone 18 years of age or older who was born after 1956 should get at least one dose of MMR vaccine, unless they can show that they have either been vaccinated or had all three diseases [measles, mumps, and rubella]," the CDC's web site states.

Pregnant women shouldn't get vaccinated until after they've had their baby. People who are allergic to the vaccine's ingredients shouldn't get it, either.

Not sure? Ask your doctor.

If you think you’ve been exposed to measles and haven't been vaccinated, can you still get the vaccine?

Yes, but you have to get it within 72 hours of exposure to be effective.

Show Sources



Aaron Glatt, MD, infectious disease specialist; spokesman, Infectious Diseases Society of America.

Kathleen Harriman, PhD, MPH, RN, chief of the vaccine preventable disease epidemiology section, California Department of Public Health.

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