title: Risk of Active Tuberculosis in the Five Years Following Infection . . . 15%?
abstract: BACKGROUND
  It is often stated that the lifetime risk of developing active TB after an index infection is 5% to 10%, one-half of which accrues in the 2 to 5 years following infection. The goal of this study was to determine whether such estimates are consistent with local programmatic data.
  
  
  METHODS
  This study included close contacts of individuals with active pulmonary TB notified in the Australian state of Victoria from January 1, 2005, to December 31, 2013, who we deemed to have been infected as a result of their exposure. Survival analysis was first performed on the assumption of complete follow-up through to the end of the study period. The analysis was then repeated with imputation of censorship for migration, death, and preventive treatment, using local mortality and migration data combined with programmatic data on the administration of preventive therapy.
  
  
  RESULTS
  Of 613 infected close contacts, 67 (10.9%) developed active TB during the study period. Assuming complete follow-up, the 1,650-day cumulative hazard was 11.5% (95% CI, 8.9-14.1). With imputation of censorship for death, migration, and preventive therapy, the median 1,650-day cumulative hazard over 10,000 simulations was 14.5% (95% CI, 11.1-17.9). Most risk accrued in the first 5 months after infection, and risk was greatest in the group aged < 5 years, reaching 56.0% with imputation, but it was also elevated in older children (27.6% in the group aged 5-14 years).
  
  
  CONCLUSIONS
  The risk of active TB following infection is several-fold higher than traditionally accepted estimates, and it is particularly high immediately following infection and in children.
authors: Victorian Tuberculosis Program at the Peter Doherty Institute, Melbourne, Australia; Centre for Population Health, the Burnet Insitute, Melbourne, Australia. Electronic address: james.trauer@mh.org.au.
authors: James M
authors: JM
authors: Trauer
authors: Victorian Tuberculosis Program at the Peter Doherty Institute, Melbourne, Australia.
authors: Nompilo
authors: N
authors: Moyo
authors: Victorian Department of Health and Human Services, Melbourne, Australia.
authors: Ee-Laine
authors: EL
authors: Tay
authors: Victorian Tuberculosis Program at the Peter Doherty Institute, Melbourne, Australia.
authors: Katie
authors: K
authors: Dale
authors: Centre for Population Health, the Burnet Insitute, Melbourne, Australia.
authors: Romain
authors: R
authors: Ragonnet
authors: Victorian Infectious Diseases Service at the Peter Doherty Institute, Melbourne, Australia; Australian Institute of Tropical Health and Medicine, James Cook University, Australia.
authors: Emma S
authors: ES
authors: McBryde
authors: Victorian Infectious Diseases Service at the Peter Doherty Institute, Melbourne, Australia; Department of Microbiology and Immunology, the University of Melbourne at the Peter Doherty Institute, Melbourne, Australia.
authors: Justin T
authors: JT
authors: Denholm
mesh_terms: D000293:Adolescent; D000995:Antitubercular Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009017:Morbidity / Q000639:trends; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000517:prevention & control; D014739:Victoria / Q000453:epidemiology
chemical_list: D000995:Antitubercular Agents
keywords: TB; TB prevention; epidemiology