Children get their first measles vaccine dose between 12 and 15 months old, with a second dose between ages 4 and 6. The vaccine is given as the MMR (measles, mumps, and rubella) combination shot, and both doses are required for school entry in all 50 states and Washington, D.C.
The Standard Two-Dose Schedule
The minimum age for the first MMR dose is 12 months. Most pediatricians give it at the 12-month or 15-month well-child visit. A single dose is 93% effective at preventing measles, which is strong but leaves a small gap. The second dose, given between ages 4 and 6 (typically before kindergarten), bumps protection up to about 97%. That second dose doesn’t wear off or need a booster. It exists mainly to catch the roughly 7% of children whose immune systems didn’t fully respond the first time around.
The timing of these doses isn’t arbitrary. Before 12 months, antibodies passed from mother to baby during pregnancy can interfere with the vaccine and prevent a strong immune response. By a child’s first birthday, those maternal antibodies have faded enough for the vaccine to work properly.
Early Doses for International Travel
If you’re traveling internationally with an infant, the timeline shifts. Babies as young as 6 months can receive an early MMR dose before traveling to areas where measles is common. This early dose offers some protection during the trip but does not count toward the routine schedule. Your child will still need the standard first dose at 12 to 15 months and the second dose at 4 to 6 years, for a total of three shots instead of two. The CDC does not recommend the vaccine for infants younger than 6 months under any circumstances.
MMR vs. MMRV: What’s the Difference
There’s also a four-in-one vaccine called MMRV, which adds chickenpox (varicella) protection to the standard MMR. It’s only licensed for children ages 1 through 12. For the first dose in children under 4, the CDC recommends giving MMR and the chickenpox vaccine as separate shots unless a parent specifically prefers the combined MMRV. For the second dose, MMRV is used more routinely. If MMRV is chosen, the second dose can be given as early as three months after the first.
Adults Who May Still Need It
If you were born in 1957 or later and never received the MMR vaccine, or you’re unsure whether you did, you likely need at least one dose. Adults born before 1957 are generally considered immune because measles circulated so widely during their childhood that virtually everyone was exposed. There’s no upper age limit for getting the MMR vaccine, and no routine booster is recommended for adults who completed their series. Immunity from two doses is considered lifelong.
Some adults need two doses rather than one. This includes college students, international travelers, and healthcare workers, all of whom face higher exposure risk.
When the Vaccine Should Be Delayed
A few situations call for postponing or skipping the MMR vaccine entirely. It should not be given during pregnancy or to anyone with a severely weakened immune system, whether from a genetic condition, chemotherapy, or advanced HIV. Children who had a serious allergic reaction to a previous dose should not receive another.
Some circumstances require a temporary delay rather than permanent avoidance. If your child has received a blood product (like a transfusion or immune globulin) within the past several months, the vaccine may need to wait because those antibodies can block the immune response, similar to how maternal antibodies do in very young infants. A moderate or severe illness is also reason to reschedule, though a mild cold is not. Children with a family history of immune deficiency in a parent or sibling should have their own immune function confirmed before vaccination.
One lesser-known interaction: if your child needs a tuberculosis skin test, it should be done either on the same day as the MMR shot or at least four weeks after. The measles vaccine can temporarily suppress the skin’s reaction to the TB test, potentially causing a false negative.