The impact of alternative delivery strategies for novel tuberculosis vaccines in low- and middle-income countries: a modelling study

Abstract Background Tuberculosis is a leading infectious cause of death worldwide. Novel vaccines will be required to reach global targets and reverse setbacks from the COVID-19 pandemic. We estimated the impact of novel tuberculosis vaccines in low- and middle-income countries (LMICs) under alternative delivery scenarios. Methods We calibrated a tuberculosis model to 105 LMICs (93% of global tuberculosis incidence). Vaccine scenarios were implemented as Basecase : routine vaccination of 9-year-olds and a one-time vaccination campaign for ages ≥10 with country-specific introduction between 2028–2047 and 5-year scale-up to target coverage; Accelerated Scale-up : as Basecase , but all countries introducing in 2025 with instant scale-up; and Routine Only : as Basecase , but routine vaccination only. Vaccines protected against disease for 10-years, with 50% efficacy. Findings The Basecase scenario prevented 44.0 (95% uncertainty range=37.2–51.6) million tuberculosis cases, and 5.0 (4.6–5.4) million tuberculosis deaths before 2050, including 2.2 million in the WHO South-East Asian region. The Accelerated Scale-up scenario prevented 65.5 (55.6–76.0) million cases and 7.9 (7.3–8.5) million deaths before 2050. The Routine Only scenario prevented 8.8 (7.6–10.1) million cases and 1.1 (0.9–1.2) million deaths before 2050. Interpretations Novel tuberculosis vaccines could have substantial impact, which will vary depending on delivery strategy. Including a campaign will be crucial for rapid impact. Accelerated introduction, more similar to the pace of COVID-19 vaccines, could increase lives saved by around 60%. Investment is required to support vaccine development, manufacturing, prompt introduction and scale-up. Funding WHO (2020/985800-0)