Prevea Health

Frequently Asked Questions About Measles


Measles is a highly contagious virus that lives in the nose and throat mucus of an infected person. It can spread to others through coughing and sneezing.

What are the signs and symptoms of measles?

Measles symptoms typically appear within seven to 14 days after the person is infected. Measles typically begins with:
  • High fever
  • Cough
  • Runny nose
  • Red, watery eyes
Two or three days after symptoms begin, tiny white spots may appear inside the mouth.
Three to five days after symptoms begin, a rash breaks out. It usually begins as flat red spots that appear on the face at the hairline and spread downward to the neck, trunk, arms, legs and feet. Small raised bumps may also appear on top of the flat red spots. The spots may become joined together as they spread from the head to the rest of the body. When the rash appears, a person’s fever may spike to more than 104 degrees Fahrenheit.

How are measles transmitted?

If a person is infected with measles, it can spread to others through coughing and sneezing. The measles virus can live for up to two hours in an airspace where the infected person coughed or sneeze. If other people breathe the contaminated air or touch the infected surface and then touch their eyes, noses or mouths, they can become infected. Measles is so contagious that if one person has it, up to 90 percent of the people close to that person who are not immune will also become infected.
Infected people can spread measles to others from four days before through four days after the rash appears.

How do I protect against measles?

CDC considers you protected from measles if you have written documentation (records) showing at least one of the following:
  • You received two doses of measles-containing vaccine, and you are a(n) —
    • school-aged child (grades K-12)
    • adult who will be in a setting that poses a high risk for measles transmission, including students at post-high school education institutions, healthcare personnel, and international travelers.
  • You received one dose of measles-containing vaccine, and you are a(n) —
    • preschool-aged child
    • adult who will not be in a high-risk setting for measles transmission.
  • A laboratory confirmed that you had measles at some point in your life.
  • A laboratory confirmed that you are immune to measles.
  • You were born before 1957.

How effective is the measles vaccine?

The measles vaccine is very effective. Two doses of measles vaccine are about 97 percent effective at preventing measles if exposed to the virus. One dose is about 93 percent effective.

How long does it take for the measles vaccine to work in your body?

For the measles vaccine to work, the body needs time to produce protective antibodies in response to the vaccine. Detectable antibodies generally appear within just a few days after vaccination. People are usually fully protected after about two or three weeks. If you’re traveling internationally, make sure to get up to date on all your MMR shots. You should plan to be fully vaccinated at least two weeks before you depart. If your trip is less than two weeks away and you’re not protected against measles, you should still get a dose of MMR vaccine.

How does the measles vaccine work?

When you get measles vaccine, your immune system makes protective virus-fighting antibodies against the harmless vaccine virus. Measles vaccine protects you from wild-type measles because if you have been vaccinated and then are exposed to someone with measles, your body remembers how to fight off the wild-type virus. That’s because the vaccine trained your immune system.

Could I still get measles if I am fully vaccinated?

Very few people—about three out of 100—who get two doses of measles vaccine will still get measles if exposed to the virus. Experts aren’t sure why. It could be that their immune systems didn’t respond as well as they should have to the vaccine. But the good news is, fully vaccinated people who get measles are much more likely to have a milder illness. And fully vaccinated people are also less likely to spread the disease to other people, including people who can’t get vaccinated because they are too young or have weakened immune systems.

I’ve been exposed to someone who has measles. What should I do?

Immediately call your doctor and let them know that you have been exposed to someone who has measles. Your doctor can:
  • Make special arrangements to evaluate you, if needed, without putting other patients and medical office staff at risk, and
  • Determine if you are immune to measles based on your vaccination record, age, or laboratory evidence.
If you are not immune to measles, MMR vaccine or a medicine called immune globulin may help reduce your risk of developing measles. Your doctor can advise you, and monitor you for signs and symptoms of measles.
If you are not immune and do not get MMR or immune globulin, you should stay away from settings where there are susceptible people (such as school, hospital, or childcare) until your doctor says it’s okay to return. This will help ensure that you do not spread it to others.

I think I have measles. What should I do?

Immediately call your doctor and let them know about your symptoms so that they can tell you what to do next. Your doctor can make special arrangements to evaluate you, if needed, without putting other patients and medical office staff at risk.
For an update on the 2019 measles outbreak, visit the CDC.
Source: Centers for Disease Control and Prevention