Cost and cost-effectiveness of tongue swab-based molecular testing for tuberculosis in the Philippines, Uganda, Vietnam, and Zambia

BackgroundTongue swabs (TS) offer a promising alternative to sputum-based molecular testing for tuberculosis. As part of the Tongue Swab Yield (TSwaY) study, we assessed the cost and cost-effectiveness of integrating TS-based testing using MiniDock MTB (Guangzhou Pluslife Biotech Co., Ltd., China) into primary healthcare in four high-burden countries. MethodsCost data were collected from primary healthcare facilities in the Philippines, Uganda, Vietnam, and Zambia. We evaluated three MiniDock MTB strategies: (1) TS-only, replacing sputum Xpert Ultra; (2) limited combined, with Xpert Ultra first-line and TS added for sputum-scarce individuals; (3) extended combined, with TS also added for those with negative or indeterminate sputum results. Additionally, we simulated an integrated combined strategy using MiniDock MTB to test sputum swabs (if available) and TS for sputum-scarce individuals. Incremental cost-effectiveness ratios (ICERs) for each scenario were estimated relative to the next least costly strategy. Net monetary benefits (NMB) were evaluated across willingness-to-pay (WTP) thresholds. Best estimates were based on observed diagnostic yield, with 95% uncertainty intervals from probabilistic simulation. FindingsAmong 1370 participants, TS-only was least costly but yielded the fewest diagnoses (62 [95% UI: 48;75] at USD 300 [95% UI: 244;388] per diagnosis). The standard of care, sputum Xpert Ultra, was extendedly dominated by TS-based strategies. Limited combined yielded 12 (95% UI: -1;22) additional diagnoses at an incremental USD 1,507 per diagnosis compared with TS-only; extended combined yielded 15 (95% UI: 8;22) additional diagnoses at an incremental USD 1,004 (95% UI: 661;1,655) per diagnosis compared with limited combined. The simulated integrated combined sputum swab and TS testing using MiniDock MTB had the highest NMB at WTP thresholds above USD 161 per additional diagnosis. InterpretationOur findings support integrating swab-based testing with MiniDock MTB into diagnostic algorithms in high-burden settings to increase case detection at minimal additional cost. FundingGates Foundation.