Dynamics of QuantiFERON-TB Gold Plus Results in a Large TB Preventive Treatment Trial Across 3 High-Burden HIV/TB Countries.
Belén Saavedra-Cervera, Dinis Nguenha, Violet Chihota et al.
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In 30 seconds
This longitudinal analysis of a randomized trial assessed serial QuantiFERON-TB Gold Plus (QFT-Plus) results in people with HIV enrolled in Ethiopia, Mozambique, and South Africa and assigned to three TB preventive treatment regimens. Testing was performed at baseline, month 12, and month 24. By month 12, 13.0% (196/1502) had converted, with similar rates for 3HP and 6H. Conversions and reversions were frequent and did not differ significantly by regimen or receipt of a second treatment course. Baseline QFT-Plus positivity was associated with higher TB risk during the study.
Key findings
- From baseline to month 12, 13.0% (196/1502) converted; rates were 13.1% with 3HP and 12.9% with 6H.
- From month 12 to month 24, conversion occurred in 4.0% with a second 3HP course and 9.4% without one (P = .110).
- Overall, 19.0% (178/935) reverted, with similar rates across treatment arms and timepoints.
- Baseline QFT-Plus positivity was associated with higher TB risk (adjusted hazard ratio, 1.66 [95% confidence interval, 1.41-1.89], P = .034).
Why it matters
Frequent QFT-Plus conversions and reversions in people with HIV in high-transmission settings complicate interpretation of serial test results, including after preventive treatment. The association between baseline positivity and subsequent TB risk also indicates that baseline results carry prognostic information in this trial population, while changes over time were not clearly differentiated by regimen.
What to keep in mind
The findings come from people with HIV in three high-burden countries and may not generalize to other populations or transmission settings. Serial QFT-Plus changes are test outcomes and do not by themselves establish the cause of conversion or reversion.