Model-based impact evaluation of new tuberculosis vaccines in aging populations under different modeling scenarios: the case of China

Front Public Health. 2024 Feb 23:12:1302688. doi: 10.3389/fpubh.2024.1302688. eCollection 2024.

Abstract

Introduction: The slow descent in TB burden, the COVID-19 pandemic, along with the rise of multidrug-resistant strains of Mycobacterium tuberculosis, seriously threaten TB control and the goals of the End TB strategy. To fight back, several vaccine candidates are under development, with some of them undergoing the phases 2B and 3 of the development pipeline. The impact of these vaccines on the general population needs to be addressed using disease-transmission models, and, in a country like China, which last year ranked third in number of cases worldwide, and where the population is aging at a fast pace, the impact of TB vaccination campaigns may depend heavily upon the age of targeted populations, the mechanistic descriptions of the TB vaccines and the coupling between TB dynamics and demographic evolution.

Methods: In this work, we studied the potential impact of a new TB vaccine in China targeting adolescents (15-19 y.o.) or older adults (60-64 y.o.), according to varying vaccine descriptions that represent reasonable mechanisms of action leading to prevention of disease, or prevention of recurrence, each of them targetting specific routes to TB disease. To measure the influence of the description of the coupling between transmission dynamics and aging in TB transmission models, we explored two different approaches to compute the evolution of the contact matrices, which relate to the spreading among different age strata.

Results: Our findings highlight the dependence of model-based impact estimates on vaccine profiles and the chosen modeling approach for describing the evolution of contact matrices. Our results also show, in line with previous modeling works, that older adult vaccination is a suitable option in China to reduce the incidence of TB as long as the vaccine is able to protect already exposed individuals.

Discussion: This study underscores the importance of considering vaccine characteristics and demographic dynamics in shaping TB control strategies. In this sense, older adult vaccination emerges as a promising avenue for mitigating TB transmission in China but also remarks the need for tailored intervention strategies aligned with demographic trends.

Keywords: bias; epidemiology; modeling; tuberculosis; vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Aged
  • Aging
  • Humans
  • Mycobacterium tuberculosis*
  • Pandemics
  • Tuberculosis Vaccines*
  • Tuberculosis* / epidemiology

Substances

  • Tuberculosis Vaccines

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. MT acknowledges the support of the Government of Aragón through a PhD contract. JS acknowledges support from the Spanish Ministry of Science and Innovation (MICINN) through grant PID2019-106859GA-I00 and Ramón y Cajal research grant RYC-2017-23560, as well as to the Government of Aragón, Spain, and “ERDF A way of making Europe” through grant B49-23R (NeuroBioSys). YM was partially supported by the Government of Aragón, Spain, and “ERDF A way of making Europe” through grant E36-23R (FENOL), and by Ministerio de Ciencia e Innovación, Agencia Española de Investigación (MCIN/AEI/10.13039/501100011033) Grant No. PID2020-115800GB-I00. The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript.