Making new tuberculosis (TB) vaccines widely available could prevent millions of cases and deaths, according to modelling by researchers at the London School of Hygiene & Tropical Medicine (LSHTM).
The research, carried out with Gavi, the Vaccine Alliance, explored the potential health and economic impact of introducing a new vaccine designed to prevent TB disease.
Researchers modelled different levels of vaccine demand across 73 low- and middle-income countries, which together account for 93% of the global TB burden in 2024.
Under a high-demand scenario, vaccines delivered between 2030 and 2050 were estimated to avert 61 million TB cases and seven million deaths by 2100. A medium-demand scenario could avert 43 million cases and five million deaths, compared with 14 million cases and 1.7 million deaths under a low-demand scenario focused only on groups at higher risk of developing TB.
While targeting only high-risk groups could result in a lower cost for each death or disability-adjusted life year (DALY) averted, the overall health benefits could be considerably smaller than when vaccines were made more widely available.
The modelling also estimated that TB vaccination could be cost-saving from a societal perspective across all three scenarios.
This finding remained when researchers tested different assumptions about characteristics of a future TB vaccine, including efficacy ranging from 30% to 70% and protection lasting between three and 20 years.
Dr John Ellis, Research Fellow at LSHTM and a member of the TB Modelling Group, who led the modelling, said
"These results show how valuable a new TB vaccine could be. They should encourage countries, donors and other stakeholders to start preparing now, so the vaccine can be rolled out as widely as possible when it becomes available."
The team used TBmod, a transmission model developed within LSHTM's TB Modelling Group, adapting it to account for the different populations that could be targeted for vaccination in each country.
The work builds on TB vaccine demand forecasts developed by Gavi, the Clinton Health Access Initiative (CHAI) and MMGH. While those forecasts explored potential demand for a future TB vaccine, the LSHTM modelling examined what different levels of rollout could mean for health and economic outcomes.
The preliminary modelling has informed Gavi's Early Market Shaping Roadmap for novel TB vaccines, which aims to prepare the global market for the introduction and rollout of new TB vaccines.
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