Interferon-gamma Release Assay and Rifampicin Therapy for Household Contacts of Tuberculosis

J Infect. 2012 Mar;64(3):291-8. doi: 10.1016/j.jinf.2011.11.028. Epub 2011 Dec 19.


Objectives: Longitudinal studies in household contacts to identify subgroups at risk of active tuberculosis are lacking.

Methods: Household contacts of pulmonary tuberculosis patients were prospectively enrolled to receive chest radiography, sputum studies, and T-SPOT.TB assay at initial visit. Repeat examinations every 6 months for 3 years, and 4-month rifampin preventive therapy for T-SPOT.TB-positive contacts were provided. We investigated factors predicting T-SPOT.TB-positivity and active pulmonary tuberculosis.

Results: 583 contacts were enrolled with a follow-up duration of 20.7 ± 9.4 months. 176 (30.2%) were T-SPOT.TB-positive initially and 32 (18.2%) of them received preventive therapy. Old age, living in the same room/house with the index case, the index case having a high smear grade (3+ ∼ 4+) and pulmonary cavitation were associated with T-SPOT.TB-positivity. Active tuberculosis developed in 9 T-SPOT.TB-positive contacts; risk factors included T-SPOT.TB-positivity without preventive therapy, living in the same room, and the index case being ≤50 years or female. 108 (61.4%) T-SPOT.TB-positive contacts had repeat examinations. Forty-five had T-SPOT.TB reversion and none of them developed active tuberculosis.

Conclusion: Household contacts who are T-SPOT.TB-positive and live in the same room as the index case are at risk of active tuberculosis and require preventive therapy and close follow-up.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antibiotics, Antitubercular / therapeutic use*
  • Contact Tracing
  • Family
  • Female
  • Follow-Up Studies
  • Humans
  • Interferon-gamma Release Tests*
  • Male
  • Middle Aged
  • Prognosis
  • Rifampin / therapeutic use*
  • Risk Factors
  • Tuberculosis / diagnosis*
  • Tuberculosis / drug therapy*
  • Tuberculosis / transmission


  • Antibiotics, Antitubercular
  • Rifampin