Modeling and analysis of transmission dynamics of tuberculosis with preventive treatment and vaccination strategies in China

In China, approximately 350 million people with latent tuberculosis infection (LTBI) are the major source of new TB cases, meanwhile, BCG vaccination for newborns and children under five fails to fully arrest the TB epidemic due to the mechanisms of vaccine failure. It is expected that widespread TB preventive treatment (TPT) and new vaccination strategies may be solutions to end TB. This work allows for TPT and vaccination strategies in a nonlinear age-structured SVEIR model with nonexponential residence times to exploit the interventions for ending TB in China. Global stability analysis reveals that the target model preserves the threshold-value dynamics in terms of the basic reproduction number so that some existing results are extended, moreover, the model is applied to fit the data of TB cases in China. Furthermore, sensitivity analysis for endemic steady state suggests that four potentially feasible interventions (i.e., amplifying the inhibition effect of infectious individuals by limiting range of their mobility, shortening the treatment duration for patients, adopting BCG revaccination and enhancing the rate of TPT) can lower the steady level of infectious individuals at endemic steady state and delay its arrival time. Finally, several multifaceted strategies composed of these interventions are compared via emulational experiments. We conclude that the target of End TB Strategy by 2035 in China would be reached just by the multifaceted strategy with moderate intensity if BCG revaccination, the duration of TPT for 2 months and a 40% completion rate are realized. This investigation sheds light on the fantastic potential applications of new TPT and vaccination strategies.