ABSTRACT
Infection with tuberculosis was studied in 3509 adolescents aged 15 years from various social groups via twice BCG revaccination by analyzing the responses to Mantoux tests with 2 TU of tuberculin purified protein derivative and by following them up for 3 years with an annual examination of the same group. The rates of infection among the teenagers was found to be 32.1% and higher (58.5%) in persons without vaccination signs, but with the latter they depend upon the time after BCG vaccination: 0.7% 3 years after the second revaccination, 30.2% after the first revaccination, and 66.8% 15 years following the first vaccination. The timely and qualitative antituberculosis immunization during twice revaccination contributes to reduced infection rates among teenagers.
