BCG skin reaction in Mantoux-negative healthy children

Background: Tuberculosis poses a great challenge, especially in children. The response of BCG Test may be different in previously vaccinated children and needs to be considered before interpreting positivity for TB. This study has been carried out to determine the pattern of BCG reaction comparing previously vaccinated with non-vaccinated children. Methods: The study was conducted in the healthy school children aged 4 - 6 years. The BCG skin reaction in Mantoux-negative children was compared between children with and without previous BCG scar. After the Mantoux and BCG Test, the analysis of variance was done as per protocol. Results: Out of 50 children previously BCG vaccinated, 39( 78%) showed exaggerated BCG test responses while out of another 50 children who were not vaccinated for TB, only 9( 18%) showed exaggerated BCG Test response ( p-value < 0.00001). Average induration obtained in children who were immunized with BCG at birth was much greater than those who were not immunized. 80% and 76% males and females respectively in Group I showed exaggerated BCG response while 16% and 20% males and females respectively of Group II showed exaggerated BCG response. Conclusion: The present study indicates that normal healthy children may have a mild exaggerated BCG Test response i.e. induration up to 8 mm because of prior BCG vaccination. Therefore, BCG Test, though important should not be the only criteria for start of chemotherapy for TB in children as the side effects of drugs may cause much morbidity. An induration up to 8 mm after the BCG Test can be normal in Indian settings due to exposure to Mycobacterium in environment and/or BCG vaccine.