A dynamic model to study the potential TB infections and assessment of control strategies in China

TL;DR

This study develops a dynamic TB transmission model for China, estimating infection numbers and evaluating control strategies, highlighting challenges and potential pathways to meet WHO elimination goals by 2035.

Contribution

The paper introduces a TB transmission model incorporating infection dynamics and vaccination, with parameter fitting and sensitivity analysis specific to China.

Findings

Estimated 39.5% of TB cases are potentially infected individuals.

Reducing TB cases by 90% by 2035 is challenging with current measures.

Combination of detection, treatment, and exposure reduction can achieve WHO goals.

Abstract

China is one of the countries with a high burden of tuberculosis, and although the number of new cases of tuberculosis has been decreasing year by year, the number of new infections per year has remained high and the diagnosis rate of tuberculosis-infected patients has remained low. Based on the analysis of TB infection data, we develop a model of TB transmission dynamics that include potentially infected individuals and BCG vaccination, fit the model parameters to the data on new TB cases, calculate the basic reproduction number \mathcal{R}_v= 0.4442. A parametric sensitivity analysis of \mathcal{R}_v is performed, and we obtained the correlation coefficients of BCG vaccination rate and effectiveness rate with \mathcal{R}_v as -0.810, -0.825. According to the model, we estimate that there are 614,186 (95% CI [562,631,665,741]) potentially infected TB cases in China, accounting for about 39.5% of the total number of TB cases. We assess the feasibility of achieving the goals of the WHO strategy to end tuberculosis in China and find that reducing the number of new cases by 90 per cent by 2035 is very difficult with the current tuberculosis control measures. However, with an effective combination of control measures such as increased detection of potentially infected persons, improved drug treatment, and reduction of overall exposure to tuberculosis patients, it is feasible to reach the WHO strategic goal of ending tuberculosis by 2035.