What is the recommended measles‑mumps‑rubella (MMR) vaccination schedule for adults, including indications for one versus two doses, the minimum interval between doses, and contraindications?

MMR Vaccination Schedule for Adults

All adults born in 1957 or later without documented immunity should receive at least one dose of MMR vaccine, with a second dose required for healthcare personnel, postsecondary students, international travelers, and those in outbreak settings, administered at a minimum interval of 28 days. 1, 2

Determining Who Needs Vaccination

Presumed Immunity

• Adults born before 1957 are generally considered immune to measles, mumps, and rubella and do not require vaccination 3, 1
• Critical exception: Healthcare personnel born before 1957 must provide documentation of immunity or receive vaccination regardless of birth year 1

Acceptable Evidence of Immunity

• Documentation of age-appropriate MMR vaccination 1
• Laboratory evidence of immunity to each disease 1
• Laboratory confirmation of disease (provider-diagnosed disease alone is not acceptable for rubella) 3, 1

One-Dose Indications

All adults born in 1957 or later without evidence of immunity require at least one dose of MMR vaccine 3, 1

All women of childbearing age without evidence of rubella immunity should receive one dose, regardless of birth year 3, 1

Two-Dose Requirements (Minimum 28-Day Interval)

High-Risk Groups Requiring Two Doses

• Healthcare personnel born in 1957 or later 3, 1
• Postsecondary students (colleges, universities, vocational schools) 3, 1, 2
• International travelers 3, 1, 2
• Adults in outbreak settings or recently exposed to measles or mumps 1, 2

Historical Vaccination Issues

• Adults who received killed measles vaccine between 1963-1967 require two doses of MMR 3, 1, 2
• Adults who received measles vaccine of unknown type between 1963-1967 require two doses 3, 1, 2
• Adults vaccinated with mumps vaccine before 1979 who are at high risk should receive two doses 3, 2

Special Consideration for Older Healthcare Workers

For unvaccinated healthcare personnel born before 1957 who lack laboratory evidence of immunity, facilities should consider routinely administering two MMR doses for measles and mumps protection 3, 1, 2

Dosing Interval

The minimum interval between first and second MMR doses is 28 days (4 weeks) 3, 1, 2

Critical Pitfall

If the second dose is inadvertently administered before 28 days have elapsed, it does not count as valid and must be repeated after the appropriate interval 1

The second dose is not a booster but addresses primary vaccine failure in persons who did not respond to the first dose 2

Special Populations

Women of Childbearing Age

• Women without evidence of immunity should receive MMR immediately after delivery or termination of pregnancy, before hospital discharge 3, 1
• Pregnancy must be avoided for 4 weeks after MMR vaccination 1

Contraindications

• Pregnancy (MMR is contraindicated during pregnancy) 1
• Severe immunodeficiency 1
• Concurrent administration with immune globulins or blood products (may diminish vaccine response) 1

Common Pitfalls to Avoid

• Do not assume healthcare workers born before 1957 are immune—they require documentation or vaccination 1, 2
• Do not accept provider-diagnosed rubella as evidence of immunity (laboratory confirmation required) 3, 1, 2
• Do not count doses given less than 28 days apart as valid 1
• Do not restart the series if doses are delayed; simply continue from where the patient left off 4