IntroductionGiven the ageing epidemic of tuberculosis (TB), China is facing an unprecedented opportunity provided by the first clinically approved next-generation TB vaccine Vaccae, which demonstrated 54.7% efficacy for preventing reactivation from latent infection in a phase III trial. We aim to assess the population-level health and economic impacts of introducing Vaccae vaccination to inform policy-makers.MethodsWe evaluated a potential national Vaccae vaccination programme in China initiated in 2024, assuming 20 years of protection, 90% coverage and US$30/dose government contract price. An age-structured compartmental model was adapted to simulate three strategies: (1) no Vaccae; (2) mass vaccination among people aged 15–74 years and (3) targeted vaccination among older adults (60 years). Cost analyses were conducted from the healthcare sector perspective, discounted at 3%.ResultsConsidering postinfection efficacy, targeted vaccination modestly reduced TB burden (~20%), preventing cumulative 8.01 (95% CI 5.82 to 11.8) million TB cases and 0.20 (0.17 to 0.26) million deaths over 2024–2050, at incremental cost-effectiveness ratio of US$4387 (2218 to 10 085) per disability adjusted life year averted. The implementation would require a total budget of US$22.5 (17.6 to 43.4) billion. In contrast, mass vaccination had a larger bigger impact on the TB epidemic, but the overall costs remained high. Although both preinfection and postinfection vaccine efficacy type might have a maximum impact (>40% incidence rate reduction in 2050), it is important that the vaccine price does not exceed US$5/dose.ConclusionVaccae represents a robust and cost-effective choice for TB epidemic control in China. This study may facilitate the practice of evidence-based strategy plans for TB vaccination and reimbursement decision making.

S1. Errors in GEOS-5 meteorological parameters 1Errors in the GEOS-5 meteorology are quantified here using observational data from ISH and 2 ISCCP. Results are exploited in Sect. 4 to evaluate the sensitivity of NO 2 columns simulated 3 by GEOS-Chem to meteorological inputs. 4To better understand the reliability of the meteorological fields, the analysis is conducted for a 5 comprehensive set of parameters including air temperature, RH, tropospheric water vapor 6 path, surface air pressure, 10m wind speed, cloud fraction, COD, and precipitation. 7Measurements are taken from the ISH dataset for air temperature, RH, surface air pressure, 8 wind speed and precipitation, and are taken from ISCCP for tropospheric water vapor path, 9