Abstract
Background: An estimated one million new cases of TB occur in children each year. Children are at a greater risk of becoming infected with TB and progressing from infection to active disease. Child contacts are a substantial population at risk for TB and a group that has great potential to benefit from screening and preventive treatment. However, there is little documentation on the management of case contacts in high burden TB settings.
Objectives: Our study sought to describe the characteristics of the child contact population eligible for screening. We determined the risk factors for child contacts attending TB screening using quantitative and qualitative methods and calculated the proportion of contacts that returned. We also wanted to estimate the risk of TB contacts becoming TB cases from routine records.
Methods: The study took place at an urban lung clinic in Indonesia. The clinic is a public, out-patient facility. Quantitative data were collected from sputum smear positive TB patients with child contacts <15 using a structured questionnaire. Clinic staff were also interviewed on perceived barriers to implementing a case contact screening program. Accounting records were reviewed to analyze costs of the screening program. In addition, contacts for TB cases diagnosed in 2007 were entered onto a database and medical records were analyzed from 2007-2009 to determine the proportion of contacts that progressed to TB cases and compared to the expected proportion from published studies.
Results: Between January and May 2011, data were collected from 100 interviews with TB cases, ten interviews with clinic staff, accounting records, and a review of 969 pulmonary TB cases and their contacts.
While 177 children were eligible for screening for either anti-TB or prophylactic treatment only 18 (10%) children returned for screening. Factors that were found to be significantly associated with screening adherence were female sex of the TB case (Adjusted OR 8.6, 95% CI 1.2-59), children who exhibited at least one TB symptom (Adjusted OR 6.7, 95%CI 1.9-24), and cases with lower travel expenses to clinic (Adjusted OR 8.9, 95%CI 1.2-64). The costs of screening for a family with two eligible children were found to be approximately 20% of the monthly income earned by these families.
1.1% of all contacts of TB cases registered at BBKPM at 2007 were found to be co-prevalent or secondary TB cases. The incidence rate of TB in sputum smear positive cases’ contacts was determined to be 303 per 100,000 person years.
Conclusions: The incidence rate of TB contacts found in this study was lower than expected. The low return rate of child contacts and the limited incidence rate of household contacts progression to active disease suggests that there are many missed opportunities to prevent and detect TB cases in the contact population. Initiating a less expensive screening method, symptom-based screening, could overcome several barriers to screening identified in this research. Contact investigation and preventive treatment are under-utilized tools in the effort to combat TB; however, barriers to their implementation in high burden settings warrant further exploration.