The standard schedule: two shots starting at 12 months

Most children in the United States receive their first measles vaccine at 12 months old, as part of the MMR shot (which protects against measles, mumps, and rubella). The second dose comes at 4 to 6 years old, before school starts. This two-dose schedule gives children strong, lasting protection against measles.

The timing matters because babies under 12 months still have some protection from their mother's antibodies, but that protection fades. By 12 months, a baby's immune system is developed enough to respond well to the vaccine. The second dose, given years later, reinforces immunity and catches the small number of children whose first dose did not fully protect them.

Key Takeaways

  • The first MMR dose is given at 12 months old, and the second at 4 to 6 years old, before school entry.
  • Children who travel internationally or are exposed to measles may receive the first dose as early as 6 to 11 months, followed by the standard second dose later.
  • Teenagers and adults who were never vaccinated or have no record of vaccination can receive both doses, spaced at least 28 days apart.
  • Pregnant people should not receive the MMR vaccine, but should receive it before pregnancy if they have no immunity.
  • Your child's doctor or local health department can tell you whether your child is on schedule and catch up if doses were missed.

Earlier vaccination for travel or outbreak exposure

If your child will travel outside the United States before age 12 months, or if there is a measles outbreak in your area, your doctor may recommend the first MMR dose as early as 6 to 11 months old. This earlier dose does not replace the standard schedule — your child will still need the regular first dose at 12 months and the second dose at 4 to 6 years.

The reason for the earlier dose is simple: measles spreads quickly in places where many people are unvaccinated, and the disease is much more serious in infants. An early dose offers some protection during the high-risk period, even though it may not be as strong as the dose given at 12 months.

Catch-up vaccination for children who missed doses

If your child missed a dose or you are unsure whether they were vaccinated, there is no need to start over. Your child can receive the next dose in the series at any time, as long as it is at least 28 days after the previous dose. Your child's doctor can check their vaccination record and tell you what is needed next.

Children can catch up at any age. A child who received their first dose at age 3 can still receive their second dose at age 4 or 5. A child who never received any MMR vaccine can start the series at any point — there is no age limit for catching up.

Vaccination for teenagers and adults

If you are a teenager or adult and were never vaccinated or have no record of vaccination, you can receive the MMR vaccine. Most people need two doses, given at least 28 days apart. Some adults — particularly those born in 1957 or earlier, or those who had measles as a child — may need only one dose or no dose at all; your doctor can advise you based on your history.

Adults who work in healthcare, education, or childcare, or who plan to travel internationally, should make sure they are vaccinated. If you are unsure whether you were vaccinated as a child, a blood test can show whether you are immune, though vaccination is often simpler and safe even if you already have some immunity.

Who should not receive the MMR vaccine

Pregnant people should not receive the MMR vaccine because it is a live vaccine (made from a weakened form of the virus). If you are planning to become pregnant and have no record of measles vaccination, you should receive the vaccine before pregnancy. If you are already pregnant, you can receive the vaccine after delivery.

People with certain severe allergies to vaccine ingredients, or those with specific immune system disorders, may not be able to receive MMR. Your doctor can review your medical history and tell you whether the vaccine is safe for you. Most people with common allergies, including egg allergies, can safely receive MMR.

What happens after vaccination

After the MMR vaccine, mild side effects are normal and expected. These include a sore arm, low fever, or a light rash that appears 7 to 10 days after the shot. These effects mean the vaccine is working and go away on their own within a few days.

Serious side effects are very rare. Your child should be observed for 15 minutes after vaccination in case of an immediate allergic reaction, though this happens in fewer than one in a million doses. If you notice anything unusual in the days after vaccination, contact your child's doctor.

Keeping track of vaccination records

Your child's doctor or clinic will give you a record card showing the date and lot number of each MMR dose. Keep this card in a safe place — you will need it for school enrollment, travel, or if you change doctors. Many states also keep vaccination records in a state registry that you can access online or by calling your health department.

If you lose your card, your doctor's office can print a new one from their records, or your state health department can help you find your vaccination history. If you have no record at all, it is safe to receive the vaccine again rather than spend time searching for old paperwork.

Frequently Asked Questions

Can my child get the MMR vaccine at the same time as other vaccines?

Yes. MMR can be given on the same day as other vaccines, though they must be injected in different arms. If your child is due for multiple vaccines, your doctor can give them all at once. This does not weaken the protection from any of them.

What if my child was vaccinated but still got measles?

This is rare but possible. About 97 out of 100 people who receive two MMR doses are protected. The small number who are not protected usually have milder illness than unvaccinated people. If your child was vaccinated and then exposed to measles, tell your doctor right away so they can monitor for symptoms.

Do I need a booster dose of MMR as an adult?

No. Two doses of MMR in childhood provide lifelong protection for most people. Adults do not need booster shots. If you received only one dose as a child, you may benefit from a second dose, especially if you work in healthcare or plan to travel internationally.

Is the MMR vaccine safe for people with egg allergies?

Yes. Although MMR is grown in eggs, the amount of egg protein in the final vaccine is extremely small. People with egg allergies, even severe ones, can safely receive MMR. Your doctor may ask you to stay for observation for 15 minutes after the shot, but this is standard precaution, not a sign of danger.

What if I do not know whether I had measles or was vaccinated?

A blood test can show whether you are immune to measles. However, getting vaccinated is also safe even if you already have immunity, so many doctors recommend vaccination rather than testing. If you choose testing, ask your doctor which option makes sense for your situation.