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Table 1 Key model input parameters

From: Tuberculosis control strategies to reach the 2035 global targets in China: the role of changing demographics and reactivation disease

Parameter Range* Source
Latent phase   
Proportion of latent disease that is binned into latent fast Range used in calibration This parameter is calibrated [73,74,98-102]
Adults: 0.05-0.35
Children: set to 1/3 of adult value
Time to progress from latent fast to presymptomatic active disease Exponentially distributed [51,52]
Mean: 0.5 year
Time to progress from latent slow to active presymptomatic disease Exponentially distributed This parameter is calibrated [51,52,55,74,99]
Range: 5-10% of latent slow reactivate in their lifetime
Relative reduction in susceptibility to reinfection due to prior exposure to TB 0.65 [74,76,103]
Active phase   
Time to progress from active presymptomatic to active symptomatic Exponentially distributed [53-59]
Mean: 1 year
Proportion of incident active symptomatic TB that is smear positive Children: 0.15 [48,60,61]
Adult: 0.585
Proportion of incident active symptomatic TB that is smear negative Children: 0.55 [48,60,61]
Adult: 0.315
Proportion of incident active symptomatic TB that is extrapulmonary Children: 0.40 [60,104-107]
Adult: 0.1
Duration of active symptomatic disease (until disease resolution) if no treatment is available Mean 5.5 years [65]
Disease resolution in smear-positive patients, proportion self-cure 0.3 [65]
Disease resolution in smear-positive patients, proportion death 0.7 [65]
Disease resolution in smear-negative and extrapulmonary patients, proportion self-cure 0.8 [65]
Disease resolution in smear-negative and extrapulmonary patients, proportion mortality 0.2 [65]
Infectiousness   
Infectiousness during latent phase 0 [50]
Infectiousness of active presymptomatic TB, relative to smear positive 0.1 [53-59]
Infectiousness of extrapulmonary TB, relative to smear positive 0 [108]
Infectiousness of smear-negative TB, relative to smear positive 0.15 [62-64]
Infectiousness during active symptomatic, smear-positive (contact rate) number of new infections per year Range used in calibration: 1–7.5 This parameter is calibrated [47,82,103,109]
Relative fitness of MDR strain 1 [66-70]
Treatment seeking   
Rate of seeking treatment Exponentially distributed [24-28,71]
Mean: 4 months
Rate of seeking retreatment (hospital) Exponentially distributed Assumption informed by expert opinion from Chinese CDC
Mean: 22 months
Rate of seeking retreatment (CDC) Exponentially distributed Assumption informed by expert opinion from Chinese CDC
Mean: 4 months
Relapsers - time from completion of treatment until relapse Exponentially distributed [76]
Mean: 9 months
  1. *Parameter ranges were derived from the literature and chosen to be consistent with prior TB modeling work and expert opinion for the available health care system in China. Values are the same for adults and children unless otherwise specified.