TB Small Group

Question 1

If a person had BCG vaccination can they expect positive PPD for their whole life?

Answer 1

immune response can wane with age, not all people with BCG vaccination will show positive PPD, vaccine is designed to protect complications like TB meningitis that young children are most susceptible to

BCG does not immunize the patient against TB, it boosts CMI reactivity to M. tb which cross reacts with memory cells sensitized to M. bovis.

Question 2

What screening method is best to rule out BCG false positive PPD?

Answer 2

interferon gamma release assay