Q: My 2 year old son got the skin test (Mantoux test) positive (15 mm size). Chest x-ray is normal (no evidence of primary TB). No skin test was done before. He was given BCG at birth. He has been suggested to take 6 months treatment with rifampicin combination. I had the skin test positive couple of years ago and had taken treatment for 6 months. The doctor examined my chest x-rays few times during the treatment and at the end he said I am a normal person and nothing to worry about. Am I spreading the infection unknowingly to my family members? Will my son be completely free from the infection after 6 months? What will be the indication - skin test negative at the end of the treatment?

A:Following a successful BCG injection at birth, all individuals should normally be positive when tested for a Mantoux reaction. Therefore, giving treatment based only on a Mantoux test does not sound appropriate. In order for anti TB treatment to be given, there should be some clinical indications of active infection, even if positive proof in the form of demonstration of the AFB bacteria is not possible.