MMR Vaccination Post-Exposure Protocol
For measles exposure, administer MMR vaccine within 72 hours to susceptible persons ≥6 months of age (except pregnant women and immunocompromised patients); if beyond 72 hours but within 6 days, give immune globulin instead. 1
Measles Post-Exposure Management Algorithm
Within 72 Hours of Exposure
MMR vaccine is the preferred intervention for most susceptible individuals in this timeframe, as it may provide protection if given promptly. 1
- Eligible recipients: Persons ≥6 months of age without contraindications 1
- Settings where MMR is preferred: Day care facilities, schools, colleges, health-care facilities, and household contacts 1
- Effectiveness: Real-world data from a 2013 NYC outbreak demonstrated 83.4% effectiveness (95% CI: 34.4%-95.8%) when MMR was given post-exposure 2
Key contraindications for post-exposure MMR:
- Pregnant women 1
- Immunocompromised persons (including those with severe HIV immunosuppression) 1, 3
- Infants <6 months of age 1
Beyond 72 Hours (But Within 6 Days of Exposure)
Switch to immune globulin (IG) as MMR is no longer effective, but IG can still prevent or modify disease. 1, 4
IG dosing:
- Standard dose (immunocompetent persons): 0.25 mL/kg IM (maximum 15 mL) 1, 4
- High-risk dose (immunocompromised persons): 0.5 mL/kg IM (maximum 15 mL) 1, 3
- Pregnant women without immunity: 0.5 mL/kg IM if injection volume manageable, or IVIg 400 mg/kg 5
IG is specifically indicated for:
- Susceptible household contacts, particularly infants ≤12 months, pregnant women, and immunocompromised persons 1, 4
- Immunocompromised patients on biologics (e.g., adalimumab) regardless of vaccination history 3
- Infants <6 months of age (though those <6 months usually have maternal antibodies) 1, 4
Special Population Considerations
Infants vaccinated before 12 months:
- Must be revaccinated with two doses of MMR starting at ≥12 months, separated by at least 28 days 1
- The early dose does not count toward the routine two-dose series 1
Immunocompromised patients:
- Give IG prophylaxis regardless of vaccination status, as they may not be protected even if previously vaccinated 1, 3
- Use the higher dose of 0.5 mL/kg (not the standard 0.25 mL/kg) 1, 3
- Do NOT give MMR vaccine for post-exposure prophylaxis 1, 3
Patients receiving IGIV therapy:
- A standard dose of 100-400 mg/kg should prevent measles if exposure occurs within 3 weeks of IGIV administration 1
- Consider additional dose if exposure occurs >3 weeks after standard IGIV 1
Critical Follow-Up After IG Administration
Any person who receives IG must subsequently receive MMR vaccine 5-6 months later (if ≥12 months old and vaccine not otherwise contraindicated). 1, 4
- This delay is necessary because passively acquired antibodies from IG interfere with vaccine response 1, 4
- Failing to provide this delayed vaccination leaves the patient vulnerable to future exposures 4
Rubella and Mumps Post-Exposure
Post-exposure MMR vaccination does NOT prevent or alter the clinical severity of rubella or mumps. 1
- However, widespread vaccination during a mumps outbreak may help terminate outbreaks 1
- IG does not prevent rubella or mumps infection and is not recommended for this purpose 1
- For pregnant women exposed to rubella who will not consider pregnancy termination, 20 mL of IG within 72 hours may reduce (but not eliminate) risk 1
Common Pitfalls to Avoid
Do not use IG to control measles outbreaks in the general population—use MMR vaccine instead. 1
Do not assume household contacts will be diagnosed within 72 hours—measles is often not recognized until after this window, making IG the more practical choice for household contacts. 1
Do not use the standard IG dose (0.25 mL/kg) for immunocompromised patients—they require the higher dose of 0.5 mL/kg. 1, 3
Do not give MMR vaccine to immunocompromised patients for post-exposure prophylaxis, even within 72 hours—they need IG instead. 1, 3
Do not forget to schedule MMR vaccination 5-6 months after IG administration—this is essential for long-term protection. 1, 4