Measles FAQs

The following FAQ's are reposted from the CDC website as a courtesy to our patients. Please visit the CDC for current and timely information.

Am I protected 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, health care 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.

For international travelers, CDC considers you protected from measles if you have written documentation (records) showing at least one of the following:

  • You received one dose of measles-containing vaccine, and you are an infant aged 6–11 months
  • You received two doses of measles-containing vaccine, and you are a person 12 months or older
  • 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% effective at preventing measles if exposed to the virus. One dose is about 93% effective.

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 system

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 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.

Explore the signs and symptoms of measles infection here >