Can Australia eliminate TB? Modelling immigration strategies for reaching MDG targets in a low-transmission setting.
BACKGROUND
The 2050 Millennium Development Goals (MDG) for tuberculosis (TB) aim for elimination of TB as a public health issue. We used a mathematical modelling approach to evaluate the feasibility of this target in a low-prevalence setting with immigration-related strategies directed at latent tuberculosis.


METHODS
We used a stochastic individual-based model to simulate tuberculosis disease among immigrants to Victoria, Australia; a representative low-transmission setting. A variety of screening and treatment approaches aimed at preventing reactivation of latent infection were applied to evaluate overall tuberculosis incidence reduction and rates of multidrug resistant disease.


RESULTS
Without additional intervention, tuberculosis incidence was predicted to reach 34.5 cases/million by 2050. Strategies involving the introduction of an available screening/treatment combination reduced TB incidence to between 16.9-23.8 cases/million, and required screening of 136-427 new arrivals for each case of TB prevented. Limiting screening to higher incidence regions of origin was less effective but more efficient.


CONCLUSIONS
Public health strategies targeting latent tuberculosis infection in immigrants may substantially reduce tuberculosis incidence in a low prevalence region. However, immigration-focused strategies cannot achieve the 2050 MDG and alternative or complementary approaches are required.
Victorian Infectious Diseases Service, Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Victoria; Department of Microbiology and Immunology, University of Melbourne, Victoria;
Justin T
JT
Denholm
Emma S
ES
McBryde
D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D001315:Australia; D003140:Communicable Disease Control / Q000379:methods; D003198:Computer Simulation; D054242:Emigrants and Immigrants; D004641:Emigration and Immigration; D006801:Humans; D015994:Incidence; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000208:ethnology / Q000382:microbiology / Q000517:prevention & control* / Q000635:transmission; D008403:Mass Screening / Q000379:methods*; D008962:Models, Theoretical; D011237:Predictive Value of Tests; D015995:Prevalence; D011634:Public Health; D012111:Residence Characteristics; D012307:Risk Factors; D014739:Victoria / Q000453:epidemiology
D000995:Antitubercular Agents
immigration; latent tuberculosis infection; mathematical model; public health; screening