Can a patient have a Quantiferon (Interferon-Gamma Release Assay) test following Measles, Mumps, and Rubella (MMR) vaccine administration?

Can a Patient Have a QuantiFERON Test Following MMR Vaccine?

Yes, a patient can have a QuantiFERON test immediately following MMR vaccine administration without any waiting period, as interferon-gamma release assays (IGRAs) like QuantiFERON are not affected by live viral vaccines.

Key Distinction: Tuberculin Skin Test vs. QuantiFERON

Tuberculin Skin Test (TST) Timing Requirements

• MMR vaccine may interfere with tuberculin skin test (TST) responses, causing temporary depression of tuberculin skin sensitivity 1
• If TST is needed, it should be administered either:
  • On the same day as MMR vaccine, OR
  • At least 4-6 weeks after MMR vaccination 1
• This interference occurs because live attenuated measles, mumps, and rubella viruses can temporarily suppress cell-mediated immune responses measured by TST 1

QuantiFERON (IGRA) Has No Such Restriction

• QuantiFERON and other IGRAs measure interferon-gamma release in response to specific TB antigens in vitro (in a laboratory tube), not in vivo immune responses
• Unlike TST, which requires an intact cell-mediated immune response in the patient's body, QuantiFERON testing is performed on blood samples outside the body
• No evidence exists that MMR or other live viral vaccines interfere with IGRA results
• The guidelines specifically mention TST interference but make no such warnings about IGRAs, indicating this is not a clinical concern

Clinical Recommendation Algorithm

For patients needing TB testing after MMR vaccination:

1. Prefer QuantiFERON or other IGRA testing - can be performed at any time without waiting
2. If TST must be used instead:
   • Administer TST on the same day as MMR vaccine, OR
   • Wait 4-6 weeks after MMR vaccination before placing TST 1

Important Caveats

• Tuberculin testing is not a prerequisite for MMR vaccination - do not delay needed MMR vaccination to perform TB testing 1
• Vaccination of persons with untreated active tuberculosis should be postponed until recovery, though this relates to the severity of illness rather than test interference 1
• The 4-6 week waiting period for TST after MMR applies to all live viral vaccines in the MMR family (measles, mumps, rubella, and varicella when given as MMRV) 1