547. Assessing the Effect of Isoniazid Window Period Prophylaxis in Healthy Close Contacts to TB Patients
Session: Poster Abstract Session: Tuberculosis Epidemiology and Diagnosis
Thursday, October 27, 2016
Room: Poster Hall
  • Assessing the Utility of Isoniazid Window Period Prophylaxis in Healthy Close Contacts to TB Patients PDF.pdf (1007.9 kB)
  • Background:

    Window period prophylaxis may be considered for close contacts of infectious tuberculosis (TB) patients, even in healthy adult contacts. One potential benefit may be to halt infection in those recently exposed. To date there have been no reported studies to assess the effect of window period prophylaxis on rates of tuberculin skin test (TST) conversion in healthy close contacts of patients with active TB. Our objective was to measure the effect of isoniazid (INH) window period prophylaxis on the rate of TST conversion among healthy close contacts to patients with active TB.


    We conducted a retrospective chart review utilizing the Cuyahoga County (Ohio) TB registry database to identify close contacts of patients with newly diagnosed, culture-positive pulmonary TB. We excluded contacts with specific indications for window period prophylaxis, including age below 5 years at initial TST, HIV-positive status, other immunosuppression. Analysis included case-control: cases were defined as patients with positive second TST and controls were patients with negative second TST. We compared exposure (INH window prophylaxis) and outcome (TST conversion, i.e. second TST positive) using with logistic regression modeling.


    Six hundred and twelve close contacts were included in the analysis. There were 24 close contacts with TST conversion (cases). INH window period prophylaxis was provided to 4 of the 24 converters. There were 588 close contacts with negative second TST (controls), of which 507 did not receive INH window prophylaxis and 81 did. We found no significant difference in rates of TST conversion between cases and controls (OR 1.25, 95% CI 0.42-3.76).


    In our analysis of INH window period prophylaxis given to healthy close contacts of TB patients we did not find a significant difference in TST conversion. Our study had several limitations, including small numbers of converters, which may limit its power. Given that the initial weeks after TB exposure offer the best opportunity to intervene with contacts, and shorter preventive therapy regimens are being developed, we propose further study of window period prophylaxis among healthy close contacts.

    Varun U. Shetty, M.D., Internal Medicine-Pediatrics, Metrohealth Medical Center, Cleveland, OH, Oksana Ivanushkina, B.S., TB Clinic, Metrohealth Medical Center, Cleveland, OH and Charles M. Bark, M.D., Metrohealth Department of Medicine, Division of Infection Diseases, Case Western Reserve University and Metrohealth Medical Center, Cleveland, OH


    V. U. Shetty, None

    O. Ivanushkina, None

    C. M. Bark, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.