image of Primary Prophylaxis to Prevent Tuberculosis Infection in Prison Inmates: A Randomized, Double-Blind, Placebo-Controlled Trial
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


In many low- and middle-income countries, tuberculosis (TB) incidence in prisons is high, exposing incarcerated populations to an elevated risk of TB infection. We conducted a randomized, double-blind, placebo-controlled trial among HIV-negative male inmates of a high TB burden prison to determine whether isoniazid given twice weekly (900 mg) for 12 months prevents TB infection. The primary outcome was QuantiFERON–TB Gold in Plus (QFT) conversion to ≥ 0.35 international units per milliliter (IU/mL) at 6 months; secondary outcomes included alternative QFT thresholds (≥ 0.7, ≥ 2.0, and ≥ 4.0 IU/mL). In total, 467 participants were randomly assigned to intervention ( = 258) or control ( = 209). In an interim analysis of participants who had completed 6 months of follow-up ( = 170), QFT conversion occurred in 20.8% (19/91) and 21.5% (17/79) of participants in intervention and control arms (efficacy: 2.9%, = 0.91), respectively. The trial was then stopped according to the trial protocol, and the remaining participants prematurely discontinued. In an analysis of secondary outcomes, the intervention arm had significantly lower rates of conversion at a cutoff of ≥ 2.0 IU/mL (efficacy: 82.6%, < 0.01). In conclusion, 900 mg of isoniazid, administered twice a week, did not effectively prevent QFT conversion at a cutoff point ≥ 0.35 IU/mL in a trial of QFT-negative inmates. Higher QFT cutoffs are associated with sustained conversion and greater protection. Future clinical trials that evaluate protection for latent infection should use the highest cutoff than that recommended by the manufacturer.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...

  • Received : 09 Feb 2020
  • Accepted : 22 Jun 2020
  • Published online : 31 Aug 2020
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error