Health and Economic Impacts of Introducing Vaccae and Enhanced Drug-Resistant Tuberculosis Management Strategies in China.

Background: China faces the highest burden of latent multidrug-resistant or rifampicin-resistant tuberculosis (MDR/RR-TB). We aim to evaluate the health and economic impacts of Vaccae (a novel TB vaccine) and enhanced drug-resistant TB (DR-TB) management strategies.

Methods: Using a compartmental model calibrated with national TB data, we evaluated nine interventions from 2025-2050: enhanced DR-TB management (S1); Vaccae vaccination for those with Mycobacterium tuberculosis infection targeting specific age groups (S2: adolescents, S3: adolescents and young adults, S4: working-age adults, S5: elderly); and combined strategies (S6: S2+S1, S7: S3+S1, S8: S4+S1, S9: S5+S1). Vaccae's efficacy was set at 0.547 for the first five years, and then waning annually by 0.036. Costs were US$28/dose for Vaccae, US$87/test for Xpert MTB/RIF (diagnostic), and US$13,818/course for BPaLM (novel short regimen). Using a cost-effectiveness frontier, we identified the optimal strategy providing the greatest health benefit while remaining cost-effective.

Results: Strategy S1 is projected to reduce MDR/RR-TB incidence and mortality by 21% (8%-46%) and 54% (38%-67%) by 2050. The combined strategy S9 (S5+S1) is more effective, reducing the incidence by 44% (35%-61%) and mortality by 68% (52%-78%), with an ICER of US$7,222 (4,460-10,779) per DALY averted compared with S1, highlighting its cost-effectiveness. Additionally, S9 could prevent 24.2 (13.5-32.9) million patient-months of second-line treatment from 2025 to 2050.

Conclusions: Prioritizing Vaccae vaccination for the elderly and enhancing DR-TB management offers a promising and cost-effective opportunity to DR-TB control in China. The findings may inform vaccination policies in other low- and middle-income countries with high MDR/RR-TB burden.