By: Andrew N. Hashikawa, MD, MS, FAAP & Adam Ratner, MD, MPH, FAAP

Measles is a highly contagious disease caused by the measles virus. The infection can lead to serious and sometimes fatal complications. Fortunately, measles is a vaccine-preventable illness.

Measles was under control in the United States, but we are seeing outbreaks again in areas where vaccination rates have fallen. (See “Should children who have not had a measles vaccine go to school during an outbreak? ” and “Measles vaccine for international travel .”)

Because measles is so contagious, outbreaks happen quickly. Most of the time, children who get measles are not up to date on recommended vaccines or are not old enough to get measles vaccine.

The childhood and adolescent immunization program in the United States led to a more than 99% decrease in measles cases since 1963. However, travelers visiting or returning to the United States from other countries can spread measles to people who are at risk and cause an outbreak.

After the first measles infection is reported in a community, it is considered an outbreak because of how quickly measles spreads. Local health experts must work quickly to identify others who were exposed so they can stop measles from spreading to others.

International travel tips for families with young children
Babies younger than age 6 months cannot be vaccinated yet but may have some protection from antibodies passed to them during pregnancy. (See “How Do Vaccines Work.”) Consider delaying travel to locations with measles outbreaks to avoid risks of severe illness.

Babies age 6 to 11 months old should receive their first MMR vaccine dose at least two weeks before traveling. They will still need the standard 2-dose series if they received a dose before age 12 months.

Babies 12 months and older should receive their first dose of MMR vaccine in addition to the other vaccines recommended at that age. Infants 12 months and older should also receive a second dose of the MMR vaccine 28 days after the first dose.

Before traveling, check for health advisories on the Centers for Disease Control and Prevention Travel Health Notices webpage. Depending on your travel destination and the activities you have planned, other vaccines may also be recommended.

How contagious is measles?

Measles is one of the most contagious diseases in the world. In fact, 9 out of 10 people exposed to measles will catch it, too, if they are unvaccinated, have not had the disease before or have a problem with their immune system. Even very brief exposure to an infected person in a shared space poses a high risk for unimmunized people.

How long is someone with measles contagious?

People with measles are contagious before they know they are sick. An infected person can spread measles easily to others 4 days before the rash appears, and they are still contagious 4 days after the rash appears.

How does measles spread?

Measles spreads from person to person and through the air from respiratory droplets from a child’s cough or sneeze. The virus can live for two hours on surfaces or suspended in the air. Someone who enters a room where someone with measles had been earlier can catch the disease. The virus can also travel along air currents and infect people in another room.

Even brief exposure to the virus poses a high risk of infection to anyone who is not up to date on measles vaccine or has not had measles before. People with conditions that weaken the immune system are also at high risk of infection.

What are the symptoms of measles?

measles-examplesCommon signs of measles infection include a high fever and rash. The rash usually appears 3 to 5 days after the first symptoms. It starts on the head and spreads down to the rest of the body.

In addition to a fever and rash, other measles symptoms may include:

Measles can also lead to serious complications, such as pneumonia, encephalitis (swelling of the brain), deafness, intellectual disability and even death.

How long does it take to get measles after being exposed to it?

Measles symptoms typically begin about 8 to 12 days after your child is exposed to the virus. If your child was exposed to someone with measles, call your pediatrician right away. They can check your child’s health records. If needed, your pediatrician can arrange to have your child examined without putting others at risk.

How long should a child with measles stay home from school?

Children with measles should stay home from school or child care until at least 4 full days after the beginning of the rash, when they are no longer contagious.

Should children who have not had a measles vaccine go to school during an outbreak?

During a measles outbreak, keep in mind:

Your pediatrician can let you know when it is safe for your child to return to school or child care. This will help avoid spreading measles to others who may be unable to receive the vaccine because of their age or due to a condition that affects their immune system.

How do you prevent the spread of measles?

Measles is a vaccine-preventable infection. About 95 of every 100 people will be protected after getting one dose of the MMR vaccine. Two doses of MMR vaccine protect 97-99 of every 100 people.

To avoid the disease, immunize according to the recommended schedule—when a child is 12 to 15 months of age and with a second dose at their checkup when they are 4 to 6 years of age. Some children at higher risk may need 3 doses if there is a disease outbreak.

Infants ages 6-12 months old can get a measles vaccine during an outbreak or before international travel to a location with an active measles outbreak.


Children who are vaccinated with MMR develop lasting immunity and protect others. When most of us have immunity to measles, it is less likely to spread. If you think that your child has been exposed to measles, call your pediatrician right away.