How many doses of the Measles, Mumps, and Rubella (MMR) vaccine are typically administered to a patient?

MMR Vaccine Dosing Schedule

The standard MMR vaccination schedule consists of 2 doses: the first dose at 12-15 months of age and the second dose at 4-6 years of age. 1

Routine Childhood Vaccination

• Children receive their first MMR dose at 12-15 months of age, as this timing allows for waning of maternal antibodies that could interfere with vaccine response 1
• The second dose is administered at 4-6 years of age, typically before kindergarten or first grade entry 1
• The minimum interval between doses is 28 days, though the standard schedule spaces them several years apart 1, 2
• If a child falls behind schedule, both doses should still be given at least 28 days apart, and there is no need to restart the series regardless of time elapsed 1

Adult Vaccination Requirements

Adults born in 1957 or later require at least 1 dose of MMR vaccine unless they have documentation of vaccination or laboratory evidence of immunity 3

High-Risk Adults Requiring 2 Doses:

• Healthcare workers 3, 4
• Students in postsecondary educational institutions 3, 4
• International travelers 3, 4
• Household or close contacts of immunocompromised persons 4

These high-risk groups should receive a complete 2-dose series with at least 4 weeks between doses 4

Special Circumstances

Women of Childbearing Age:

• At least 1 dose of MMR is required for all women of childbearing age who lack documentation of vaccination or serologic evidence of immunity 3, 4
• Vaccination should be offered at every healthcare encounter, including family planning visits and postpartum before hospital discharge 3

International Travel:

• Infants aged 6-11 months traveling internationally should receive a single dose of MMR before departure 3, 1
• This early dose does not count toward the routine 2-dose series, and these children must be revaccinated with 2 doses starting at 12-15 months of age 3

Outbreak Settings:

• Infants aged 6-11 months should receive a single dose during measles outbreaks 1
• Adults who received killed measles vaccine or unknown vaccine type during 1963-1967 require 2 doses 3

Evidence of Immunity

Acceptable evidence includes:

• Documentation of age-appropriate vaccination (2 doses for most populations, 1 dose for adults not at high risk) 1
• Laboratory evidence of immunity 1
• Laboratory confirmation of disease (physician diagnosis alone is no longer acceptable) 2
• Birth before 1957 (generally considered immune to measles and mumps, though healthcare workers should still be vaccinated regardless) 3, 4

Key Clinical Pitfalls

• Do not accept physician-diagnosed disease as evidence of immunity without laboratory confirmation—this criterion was removed from ACIP guidelines in 2012 2
• Do not assume women born before 1957 are immune to rubella if they are of childbearing age; they still require vaccination or serologic confirmation 3
• Do not count MMR doses given before 12 months of age toward the routine series, as maternal antibodies may interfere with seroconversion 3, 4