Contact screening and risk factors for TB among the household contact of children with active TB: a way to find source case and new TB cases

Background: Source case investigation, for children with tuberculosis (TB), is conducted to establish the source of infection and to minimize the extent of on-going transmission from infectious persons in the community. The aim of the study was to evaluate the secondary TB cases and to investigate the risk factors in developing TB among the household contacts (HHC) of children with active TB. Methods: A prospective cross-sectional study was conducted where 443 caregivers, of 508 children with active TB receiving treatment, were interviewed using a structured questionnaire. Logistic regression analysis was used to examine the risk factors for TB. Results: A total of 2397 family members at the median of 5 persons were recorded. Of these, 223 (9.3%) were screened on symptoms basis and 35 (15.7%) of these contacts were diagnosed with TB. Multivariate analysis revealed HHC with TB (OR = 15.288, 95% CI: 5.378-43.457), HHC with smoking (OR = 7.094, 95% CI: 2.128-23.648), and contact of > 18 h with TB individual (OR = 4.681, 95% CI: 1.198-18.294) as statistically significant risk factors of TB among the HHC. Conclusion: With the current system of contact screening for TB, only 9.3% of all HHC were screened. The low rates of contacts screened are possibly a repercussion of the passive nature of the program, which mainly depend on distinctive clinical symptoms being experienced by the contacts. Strategies are required to certify adherence with contact screening among children with active TB and to critically consider the factors responsible for TB transmission.