Does delay in BCG vaccination cause TB?
Q: My 5 years old daughter and 3 and half years old son stayed in India for almost one and a half years. Both of them were given BCG vaccine when they were about seven months old. Recently, the pediatrician did the PPD (tuberculin skin) test and measured it as 21 mm for my daughter and 17 mm for my son. The pediatrician prescribed isiniazid 4 table spoons a day for the next 9 months for both my kids. Is it OK to put them on INH only on the basis of Mantoux test? Is there any test to prove that they are really exposed to TB? Has delay in BCG vaccination caused this?
A:As per current guidelines, children below 5 years of age with a positive Mantoux test need to be put on INH prophylaxis and both your children have strongly positive tests. It is very unlikely that a delay in vaccination has caused this. Like all tests, there is a small probability that these could be false positive but the magnitude of the reaction makes it unlikely.