TB Tests & mRNA COVID-19 Vaccines

Arizona Department of Health Services sent this bulletin at 01/28/2021 06:31 PM MST

PHL

Dear Licensed Health Care Institution Providers,
 
On January 7, 2021, the Centers for Disease Control and Prevention ("CDC") issued a "Dear Colleague Letter" titled "TB Tests and mRNA COVID-19 Vaccines" ("letter").  This letter addresses questions that some may have about the interaction between new COVID-19 mRNA vaccines and tests used for tuberculosis (TB) infection and states the following:
 

"There are no data to inform the impact of the COVID-19 mRNA vaccines on either the tuberculin skin test (TST) (administered by intradermal placement of 0.1 cc of purified protein derivative) or the interferon gamma release assay (IGRA). There is no immunologic reason to believe that a TST or blood draw for IGRA will impact the effectiveness of COVID-19 mRNA vaccines. 

According to the Vaccine Recommendations and Guidelines of the Advisory Committee on Immunization Practices (ACIP), inactive vaccines do not interfere with TB test results. Vaccination with live viruses (such as the MMR vaccine) can cause mild immune system suppression, and may reduce the reactivity of the TST, possibly causing a false-negative reaction.

Although the COVID-19 mRNA vaccine is not a live virus vaccine, not enough is yet known of the potential impact of mRNA vaccines on immune responses to say conclusively whether the COVID-19 mRNA vaccine could have a potential effect on TST or IGRA test results during the first 4 weeks after COVID-19 vaccination.

For healthcare personnel or patients who require baseline TB testing (at onboarding or entry into facilities) at the same time they are to receive a COVID-19 mRNA vaccine, CDC recommends:

  • Perform TB symptom screening on all healthcare personnel or patients.
  • If using IGRA, draw blood prior to COVID-19 mRNA vaccination.
  • If using TST, place prior to COVID-19 mRNA vaccination.
  • If COVID-19 mRNA vaccination has already occurred, defer TST or IGRA until 4 weeks after completion of 2-dose COVID-19 mRNA vaccination.

For healthcare personnel who require testing for other reasons, CDC recommends:

  • Perform TB symptom screening on all healthcare personnel.
  • Test for TB infection before or during the same visit as COVID-19 mRNA vaccination. If this is not possible, prioritization of testing for TB infection needs to be weighed with the importance of receiving COVID-19 mRNA vaccination based on potential COVID-19 exposures and TB risk factors.
    • Healthcare personnel with high-risk conditions for TB progression should be fully evaluated as soon as possible.
    • Healthcare personnel without high-risk conditions for TB progression should proceed with contact tracing (symptom screening, chest radiograph or other imaging, specimen for microbiologic evaluation) but delay being tested for TB infection (with either TST or IGRA) if prioritized for receiving COVID-19 mRNA vaccination.

All potential recipients of COVID-19 mRNA vaccination should weigh the risks and benefits of delaying TST/IGRA with their healthcare providers. 

Please note that if an individual is due to obtain a Mantoux skin test or other TB screening test per A.A.C. R9-10-113, they may choose to do so per the CDC recommendations above.  If a COVID-19 mRNA vaccination has already occurred and a TST or IGRA is deferred until 4 weeks after completion of 2-dose COVID-19 mRNA vaccination, the reason for the late TB screening test must be documented in the individual's medical or personnel record, as applicable.     

Thank you,

Branch of Health Care Institution Licensing
Arizona Department of Health Services