The standard schedule: two shots between age 1 and age 6

Most children in the United States receive the measles vaccine as part of the MMR vaccine (measles, mumps, rubella), given in two doses. The first dose is at 12 to 15 months old. The second dose is at 4 to 6 years old, before school entry.

This two-dose schedule is what the CDC recommends for routine childhood vaccination. The spacing between doses matters: the second shot works better if it comes at least 28 days after the first. If your child received both doses on this timeline, they are considered fully protected.

Some children need a different schedule. If a child was vaccinated before 12 months (because of travel or outbreak risk), that dose does not count, and the two-dose series starts over at 12 months. If a child received only one dose by school age, the second dose must be given before enrollment.

Key Takeaways

  • The first MMR dose is given at 12 to 15 months; the second at 4 to 6 years, with at least 28 days between them.
  • A dose given before 12 months does not count toward the two-dose series and must be repeated starting at 12 months.
  • Children need both doses before school entry; most states require proof of vaccination for enrollment.
  • Teenagers and adults who were never vaccinated or have no record of vaccination can receive both doses on an accelerated schedule (28 days apart).
  • Vaccination timing may shift if a child is severely immunocompromised or if there is an active outbreak in your area.

Why the first dose waits until 12 months

Infants under 12 months still carry maternal antibodies from their mother's blood—protection passed through the placenta and breast milk. These antibodies interfere with the vaccine, making it less effective if given too early. At 12 months, those maternal antibodies have faded enough that the vaccine can work.

There is an exception: if an infant will travel internationally or if there is a measles outbreak, a dose can be given as early as 6 to 11 months. This early dose does not count as part of the official two-dose series, so the child still needs the standard first dose at 12 to 15 months, followed by the second dose at 4 to 6 years.

Catch-up vaccination for children who missed doses

If your child is older than 6 and has not received two doses, the second dose should be given as soon as possible—there is no waiting period. The only requirement is that the two doses are at least 28 days apart.

If your child is school-age and has no vaccination record, contact your pediatrician or local health department. Most states will not allow school enrollment without proof of two doses or a medical or religious exemption (rules vary by state). Getting the vaccine before school starts avoids enrollment delays.

Vaccination for teenagers and adults

Anyone born in 1957 or later who has no record of measles vaccination or immunity should receive two doses of MMR, 28 days apart. People born before 1957 are generally considered immune from natural infection, though vaccination is still an option.

Adults who received only one dose as a child need one additional dose. Healthcare workers, college students, and people planning international travel should confirm they have two doses; if records are missing, it is safer to receive the vaccine again than to guess about immunity.

Special situations that change the schedule

Children with certain medical conditions—including HIV, leukemia, or other conditions affecting the immune system—may not receive the live MMR vaccine. Their doctors will determine whether an inactivated measles vaccine is an option or whether vaccination should wait until immunity improves. Timing depends on the specific condition and treatment plan.

During a measles outbreak, health departments may recommend vaccination outside the standard schedule. If you live in or travel to an area with confirmed cases, contact your local health department or pediatrician for guidance on timing.

Pregnancy is a reason to delay MMR: the vaccine is live and not given during pregnancy. Women of childbearing age who are not immune should be vaccinated before becoming pregnant, with a recommendation to wait at least 28 days before trying to conceive.

How to find your child's vaccination record

Your pediatrician's office keeps a copy of your child's vaccines. If you have moved or changed providers, you can request records from the previous office. Many states also maintain a vaccine registry that you can search online or by phone—ask your health department for the name and website.

If records are truly lost and you cannot locate them, it is not necessary to repeat every vaccine. Your doctor can order a blood test to check for measles immunity. If immunity is confirmed, no additional vaccine is needed. If immunity is not present, vaccination can proceed regardless of what was given in the past.

What happens after the vaccine is given

Mild side effects are common: arm soreness, low fever, or a light rash 7 to 10 days after the shot. These are normal and fade on their own. Serious side effects are rare.

After the second dose, your child is considered fully protected. Protection lasts a lifetime in nearly all cases. Booster doses are not needed.

Frequently Asked Questions

Can my child get the two doses closer together than 28 days?

No. The CDC requires at least 28 days between doses for the second dose to be effective. If doses are given fewer than 28 days apart, the second dose does not count, and a third dose must be given at least 28 days after the second.

What if my child had measles? Do they still need the vaccine?

No. Natural infection provides lifelong immunity. However, if you are unsure whether your child actually had measles (rather than another illness), a blood test can confirm immunity. If immunity is confirmed, vaccination is not needed.

Is the MMR vaccine safe for children with egg allergies?

Yes. The MMR vaccine does not contain eggs and is safe for children with egg allergies. Severe allergies to gelatin or neomycin (an antibiotic in the vaccine) are rare reasons to avoid it, but your pediatrician can discuss your child's specific allergies.

Do I need to show proof of vaccination for school?

Most states require proof of two MMR doses for school enrollment. Some states allow medical or religious exemptions. Check your state or local school district's requirements; they are posted on the school or health department website.

My child was vaccinated abroad. Is that record accepted in the US?

Yes, if the vaccine record is clear and shows two doses of MMR or measles-containing vaccine given at least 28 days apart. Bring the original record to your pediatrician, who can add it to your US medical file. If the record is unclear or missing, your doctor may recommend revaccination to be certain.