1. We disagree. Studies have demonstrated >90% scar formation post-vaccination with BCG(1-5). These data indicate that a BCG scar is indeed a sensitive and reliable indicator of BCG vaccination. However, we do concur with Dr. Kartha that a prospective study could have had more validity but temporal and resource limitations ruled this out.

2. We do not deny that the use of a differential cut-off is unconventional. The multiple reasons for using this strategy have been described in detail in the article. Our hypothesis is that, despite tuberculin reactions appearing similar in both groups (as suggested by the data and pointed out by Dr. Kartha), vaccinated and unvaccinated children, ipso facto, have different risks of acquiring tuberculosis and developing disseminated disease that necessitates a different tuberculin cut-off reading for each group. It is an extension of the same logic that dictates >5mm being considered a positive reaction in an HIV infected individual.

Anoop S Pulickal,
Department of Paediatrics,
John Radcliffe Hospital,
Oxford OX3 9DU, UK.
E-mail: [email protected]