[Factors predicting new tuberculosis infections and tuberculin conversions in a contact tracing system].

Objective: To study new cases of latent tuberculosis (TB) infection, active TB and tuberculin conversions detected by means of a system for tracing the contacts of TB patients and to analyze the factors that predict the appearance of new cases.

Method: We performed a longitudinal, prospective study of all contacts of patients with active TB in the health district of Vigo, Pontevedra, in 2005 and 2006. The total rate of positive tuberculin test results and the percentage of tuberculin conversions at the end of the study were analyzed.