A New Formula for BCG Scar and Tuberculin Test Response

Abstract

Tuberculosis is an important disease in the world especially in developing and undeveloped regions and PPD test is the standard test for diagnosis of this infectious disease [1-3]. BCG vaccination has proven to be the most effective technique for controlling tuberculosis in the world especially in developing countries [1]. The BCG vaccination is the most extensively used immunization worldwide, nevertheless it can effect in the correct interpretation of the PPD test [3]. The rates of positive Tuberculin Test responses and BCG scar after BCG vaccination vary between surveys and different regions in the world [2-13]. PPD test after vaccination can evaluate the immunogenic activity and protective efficacy of the, BCG immunization at birth is common in China. In a multi-site prospective cohort study, the immunological reactivity against BCG is evaluated in four prefectural cities in China [1]. According to their results, not only the BCG vaccination among newborn infants in China causes satisfactory immune response, but also BCG scars provide a useful marker of immunization response in Chinese infants. BCG scarring and PPD reactivity possibly linked to better child survival in low-income countries. Therefore, in a study, determinants for Tuberculin test reaction and scarring was investigated in Guinea-Bissau [2]. In the multivariable analyses of BCG-vaccinated children evaluated at 6 months of age, monitoring of vaccination technique and type of BCG vaccine were important. It is concluded that vaccination technique and BCG strain are important for Tuberculin test reaction and scarring in response to BCG vaccination. Considering that these responses are associated with better infant survival, the importance of monitoring vaccination technique and of different BCG strains must be assessed with regard to infant mortality. PPD reactivity and BCG scarring have been argued as valid markers of BCG effectiveness for prevention of tuberculosis [2,8-16]. We therefore aim to evaluate BCG scars and Tuberculin test response after BCG vaccination in 4 year children in Birjand City, Iran (exactly 4 years old).