BCG status in children with tuberculosis: A multicenter study in northern Nigeria
Background: Bacille Calmette.Guerin (BCG) vaccine has been in use since 1921, yet childhood TB is still very prevalent in Nigeria. Since BCG efficacy depends in part on appropriate vaccine utilization, this study was designed to investigate the current practice of BCG administration through determination of BCG status.
Methodology: Consecutive HIV negative children with new diagnosis of tuberculosis disease attending five outpatient clinics in Northern Nigeria were recruited over 2 years. Using a structured questionnaire, information with regards to their BCG status was obtained and each child was examined for the presence of a BCG scar. Logistic regression was performed to identify determinants of BCG status.
Results: There were 300 children aged between 1 month and 14 years. More than half of them (mainly residing in rural and semiurban areas) did not receive BCG and only one.third (49/138) of those vaccinated had identifiable BCG scars. Delivery at home was significantly associated with non.receipt of the BCG antigen (OR = 408, z =5.891, P < 0.001). Lack of BCG vaccination was a significant factor for extra pulmonary disease (ƒÔ2 = 37.34, OR = 11, P = 0.0001); with a four.fold increase in relative risk. Logistic regression showed that lack of a BCG scar correlated significantly with vaccination in non.governmental facilities (P = 0.006), positive tuberculin skin test (TST) values (P < 0.0001) but not with extra pulmonary disease (P = 0.909).
Conclusion: Childhood TB is still driven to a large extent by low BCG coverage. In a TB endemic region, the absence of a BCG scar in a symptomatic child is an indicator for TB screening.