Most people need two doses of the MMR vaccine, and for many, those two doses provide lifelong protection against measles and rubella. The standard schedule places the first dose between 12 and 15 months of age and the second between ages 4 and 6. After that, no routine boosters are needed, though certain situations call for additional doses or verification of immunity.
The Standard Childhood Schedule
The CDC recommends two doses of MMR for children:
- First dose: 12 through 15 months old
- Second dose: 4 through 6 years old, before school entry
The second dose isn’t a booster in the traditional sense. It exists because a small percentage of children don’t develop full immunity after the first shot. The second dose catches those kids, bringing the overall protection rate up significantly. Once a child has received both doses on schedule, they’re considered fully vaccinated and don’t need any additional MMR shots as part of routine care.
What Adults Need to Know
If you were born in 1957 or later and never received the MMR vaccine, or you’re unsure of your vaccination history, you should get at least one dose. People born before 1957 are generally considered immune because measles, mumps, and rubella circulated so widely during their childhood that nearly everyone was exposed.
For most adults, a single dose is sufficient as a catch-up. However, two doses are recommended if you fall into a higher-risk category: healthcare workers, college students, and international travelers. If you need two doses as an adult, the second should come at least 28 days after the first.
A blood test (called a titer) can confirm whether you still have immunity. This is sometimes requested by employers, schools, or immigration authorities. If the test shows adequate antibodies, you don’t need additional vaccination regardless of whether you can find your old records.
Healthcare Workers and Students
Healthcare workers face stricter requirements because they’re more likely to encounter infected patients and could spread the disease to vulnerable people. Most healthcare facilities require staff to show proof of two doses of MMR or demonstrate immunity through a blood test. State laws vary on exactly how this is enforced, but the expectation is consistent: two documented doses or lab-confirmed immunity.
Many colleges and universities have similar requirements for enrollment, typically asking for proof of two doses before students can register for classes. If you’re heading to college and can’t locate your vaccination records, getting two doses spaced 28 days apart is the simplest path forward.
Before International Travel
Travel to countries where measles is common calls for extra precaution. The CDC recommends being fully vaccinated at least two weeks before departure. If your trip is less than two weeks away and you’re not protected, getting a dose before you leave still offers some benefit.
The travel recommendations differ by age group. Infants between 6 and 11 months can receive an early dose before traveling, but that dose doesn’t count toward the routine schedule. Those babies will still need a dose at 12 through 15 months and another at 4 through 6 years, for a total of three shots. Teens and adults with no evidence of immunity should get their first dose immediately and the second 28 days later.
Infants younger than 6 months should not receive the MMR vaccine, even for travel.
How Long Does Immunity Last?
Protection against measles and rubella from the MMR vaccine is typically lifelong. Two doses and you’re set for good. Mumps is the exception. Immunity against mumps can fade over time in some people, which is one reason mumps outbreaks still occasionally occur in vaccinated populations, particularly on college campuses and in other close-quarters settings.
Despite this, there is no recommendation for a routine third dose. Even during active measles outbreaks, the CDC does not advise a third dose of MMR. If you’ve had your two doses, your protection against measles remains strong.
Timing Around Pregnancy
The MMR vaccine contains live, weakened viruses and should not be given during pregnancy. If you’re planning to become pregnant, the recommendation is to wait at least one month after receiving the vaccine before conceiving. Ideally, a blood test should confirm your immunity before you start trying. If you discover during pregnancy that you lack immunity, vaccination should wait until after delivery.
Quick Reference by Situation
- Fully vaccinated child (2 doses on schedule): No further doses needed
- Adult born after 1957, unsure of history: At least 1 dose
- Healthcare worker or college student: 2 documented doses or a positive titer
- International traveler without evidence of immunity: 2 doses, 28 days apart
- Infant traveling internationally (6 to 11 months): 1 early dose, then resume the normal 2-dose schedule
- Born before 1957: Generally no vaccination needed