Tuberculosis control in Asia and the western Pacific: a role for computer modelling

Despite the availability of effective treatment, tuberculosis (TB) causes more deaths than any other infection. Most of the world's TB cases and deaths occur in Asia and the Western Pacific, and the growing prevalence of multiple drug-resistant TB and the spread of human immunodeficiency virus (HIV) present ever greater obstacles to effective TB control. The management of TB remains difficult, and epidemiologic studies to assess control programmes require significant time and expense and may not be generalizable to other regions. Computer models are powerful and relatively inexpensive tools for rapidly planning and evaluating TB control strategies. Models have demonstrated the value of targeted chemoprophylaxis strategies for the prevention of TB among HIV-infected individuals, and programmes to ensure that all HIV-infected individuals receive TB chemoprophylaxis should be considered in Asia and the Western Pacific. Though directly observed therapy (DOT) is effective when designed to be attractive to patients, modelling has shown that DOT, if poorly accepted by patients, may lead to fewer patients seeking care and thus to paradoxical rises in TB case rates. Models may be used to make accurate predictions of TB morbidity and programme costs using local epidemiologic and demographic inputs. The use of models in Asia and the Western Pacific offers a low-cost way to compare programmes, to improve the evaluation of programmes, to project future cases, and to examine programme needs while providing insights into TB control helpful to countries in and out of the region.