Tuberculosis control strategies to reach the 2035 global targets in China: the role of changing demographics and reactivation disease
Significant progress in tuberculosis (TB) control has been achieved worldwide over the last two decades. Global TB mortality has fallen by 45%, and TB incidence is declining. Recently, the World Health Organization (WHO) established an ambitious post-2015 global strategy, the End TB Strategy. This strategy outlines a 2025 milestone of 50% reduction in incidence and 75% reduction in mortality, and an overall 2035 target of 90% reduction in incidence and 95% reduction in mortality. In order to reach these targets, countries will likely need to redouble their TB control efforts and perhaps adopt new TB control strategies.
All of the modeled interventions are parameterized based on feasibility within the existing health care ecosystem of private hospitals and public CDC clinics. The relative impact of these interventions is described in Table 2 and shown in Figure 4.
Future intervention strategies
Impact of interventions on TB incidence and mortality from 2010 to 2035. A, B. None of the feasible interventions, even in combination (bright green), achieve the 2035 incidence or mortality targets. Also shown are the feasible interventions in isolation: baseline (black), expand DOTS (yellow), new drugs (orange), and reduced time to treatment (brown). C, D. Addition of preventative therapy to the feasible interventions (dark blue line) is likely to nearly reach the 2035 targets for both incidence and mortality. Preventative therapy alone (dark green) and active case finding plus preventative therapy (brown) also shown. The 2025 milestone (red dashed line) and 2035 target (red solid line) are calculated from 2015 model estimated mean value. Shaded area represents 95% credible interval including both parameter and stochastic uncertainties.
Conclusions: The combination of an aging demographic in China and the increasing role of reactivation disease represents a growing challenge to TB control as China considers its post-2015 strategy.
Our work shows that if the status quo DOTS strategy is maintained, the TB burden in China will decline but will not reach the 2025 milestones, even if an additional decade is provided. However, additional data are necessary to better specify what the baseline incidence trajectory might be, as projections from different points in the calibration parameter space are divergent over the next 20 years.