Can I get the measles if I've already been vaccinated?

Answers from James M. Steckelberg, M.D.

It's possible, but very unlikely. The combination measles-mumps-rubella (MMR) vaccine is a two-dose vaccine series that effectively protects against all three viruses.

In fact, more than 93 percent of people who get the first dose of MMR develop immunity to measles. After the second dose, about 97 percent of people are protected.

The first dose of the MMR vaccine is recommended for children ages 12 months to 15 months. The second dose is recommended before your child begins kindergarten or first grade, around ages 4 to 6. If needed, however, the second dose can be given as soon as four weeks after the first dose.

Your child may need the second dose at a younger age if you plan to travel abroad. Infants ages 6 months to 11 months should receive one dose of measles vaccine before traveling.

The combined measles-mumps-rubella-varicella (MMRV) vaccine is another option for children that also protects against chickenpox (varicella). It's a single shot that may be used in place of the MMR and chickenpox vaccines. Talk to your doctor about both options.

If you're a teen or adult who isn't sure whether you've been properly vaccinated against measles, talk to your doctor. A blood test can confirm if you already have immunity from a previous vaccine.

If the test shows you don't have immunity, and you're a teen or young adult living in dormitory, your doctors will likely recommend that you get two doses of vaccine at least four weeks apart. Adults who don't have immunity are advised to get at least one dose of MMR vaccine. Your doctor can recommend what's best for your individual situation.

July 11, 2018 See more Expert Answers