TB Skin Test Administration with TDAP, MMR, and Varicella Vaccines
Yes, a tuberculosis skin test can be placed on the same day as TDAP, MMR, and varicella vaccines. This is the recommended approach to avoid delays in either tuberculosis screening or vaccination.
Key Timing Principle
The tuberculin skin test should be administered either on the same day as MMR and varicella vaccines, or delayed for at least 4-6 weeks after vaccination. 1, 2 This recommendation exists because live attenuated measles, mumps, rubella, and varicella vaccines can temporarily suppress tuberculin reactivity, potentially causing false-negative results if the TST is placed 1-3 days after vaccination. 1
Evidence Supporting Same-Day Administration
Measles-containing vaccine can be administered on the same day as tuberculin skin testing without affecting test validity. 1 The immunologic suppression does not occur within the first 48 hours after measles vaccination, making simultaneous administration safe and effective. 1
A 1975 field study of 110 tuberculin-positive children demonstrated that tuberculin testing performed simultaneously with measles, mumps, or rubella vaccines showed no significant difference in test results compared to controls. 3 Only 3% of vaccinated children showed reversion to negative tine tests, identical to the 3.6% reversion rate in unvaccinated controls. 3
The FDA-approved MMR vaccine label explicitly states that tuberculin skin testing should be administered before, simultaneously with, or at least 4-6 weeks after MMR vaccination. 2
Why This Timing Matters
If tuberculin testing cannot be performed on the same day as MMR vaccination, the test should be postponed for ≥4 weeks after vaccination to avoid false-negative results. 1 This suppression of tuberculin reactivity is temporary and resolves after approximately 4-6 weeks. 1
Live-attenuated vaccines including measles, mumps, rubella, and varicella can cause suppression of the PPD response in patients infected with M. tuberculosis. 1 This suppression does not appear within the first 48 hours, which is why same-day administration is acceptable. 1
TDAP Vaccine Considerations
TDAP is an inactivated vaccine and does not interfere with tuberculin skin testing at any interval. 1 There are no timing restrictions between TDAP administration and TST placement. 1 Inactivated vaccines can be administered at any time before or after tuberculin testing without affecting test interpretation. 1
Practical Implementation Algorithm
Follow this approach for same-day administration:
- Place the tuberculin skin test intradermally on one forearm 1
- Administer MMR vaccine subcutaneously (0.5 mL) at one anatomic site 4, 2
- Administer varicella vaccine subcutaneously (0.5 mL) at a separate anatomic site 4
- Administer TDAP vaccine intramuscularly (0.5 mL) at a third site 4
- Schedule TST reading for 48-72 hours later 1
Common Pitfalls to Avoid
Do not place the TST 1-3 days after MMR or varicella vaccination. 1 This is the critical window when immunologic suppression can cause false-negative results. If vaccines were already given without TST placement, wait at least 4 weeks before tuberculin testing. 1, 2
Do not delay necessary vaccinations to perform tuberculin testing on a different day. 1 The evidence clearly supports same-day administration, and delaying vaccines leaves children unprotected against preventable diseases. 5, 4
If urgent tuberculin testing is needed after recent MMR/varicella vaccination (within 4 weeks), proceed with testing but interpret results with caution, understanding that reactivity might be reduced. 1 Consider using interferon-gamma release assays (IGRAs) as an alternative in this situation if available. 6
Special Considerations
For children under 3 years of age with prior BCG vaccination, the BCG vaccine itself may cause false-positive TST results. 6 This is separate from the MMR/varicella suppression issue and should be considered when interpreting results. 6 The risk of BCG-related false-positives disappears 3 years after vaccine administration. 6
All vaccines and the TST can be administered during the same clinical visit, maximizing efficiency and ensuring timely protection. 5, 4 This approach is strongly supported by ACIP guidelines and increases vaccination coverage by reducing missed opportunities. 1, 5, 4