Objective: The risk that latent infection will progress to active tuberculosis is greater in infants and children than for most other age groups. We set out to determine the rate of transmission of Mycobacterium tuberculosis to pediatric patients exposed to a pediatrician with smear-negative and culture-positive pulmonary tuberculosis. We also explored factors associated with compliance to prophylaxis.
Methods: Clinic and hospital billing records were used to identify patients age 5 or less who were seen during the pediatrician's potential contagious period. Patient were notified by registered mail of their putative exposure and were offered a tuberculin skin test screening with 5 tuberculin units of purified protein derivative (Tubersol, Connaught) and chest radiography of children with a tuberculin skin test > or =5 mm.
Results: A total of 456 patients were identified as exposed; 140 contacts never responded for evaluation and 93 letters were not delivered because of incorrect mailing addresses. Of the 223 who completed screening 1 (0,4%) had a initial skin test result of 8 mm. The remaining 222 contacts had repeated negative test results. The only positive child (15 months old) was born in Honduras and had received Calmette-Guerin bacillus at birth. No active tuberculosis cases were identified in the 456 contacts up to 2 years after exposure. Compliance with prophylaxis was associated with having two or less children in the household (odds ratio, 2.5; 95% confidence interval, 1.1 to 5.9).
Conclusion: We found no evidence of transmission of M. tuberculosis in an outpatient pediatric setting. Only 43% of exposed children completed screening, and 38% of those offered prophylaxis completed their initial 3 months of therapy.