Interferon-gamma release assay and Rifampicin therapy for household contacts of tuberculosis.
OBJECTIVE
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.


CONCLUSIONS
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.
Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Jann-Yuan
JY
Wang
Chin-Chung
CC
Shu
Chih-Hsin
CH
Lee
Chong-Jen
CJ
Yu
Li-Na
LN
Lee
Pan-Chyr
PC
Yang
D000328:Adult; D000368:Aged; D000904:Antibiotics, Antitubercular / Q000627:therapeutic use*; D016358:Contact Tracing; D005190:Family; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D059425:Interferon-gamma Release Tests; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012293:Rifampin / Q000627:therapeutic use*; D012307:Risk Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy* / Q000635:transmission
D000904:Antibiotics, Antitubercular; D012293:Rifampin