Predicting the Long-Term Impact of Antiretroviral Therapy Scale-Up on Population Incidence of Tuberculosis
Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; TB Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom; Desmond Tutu HIV Centre, University of Cape Town, Cape Town, South Africa; HIV and TB Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
Objective:To investigate the impact of antiretroviral therapy (ART) on long-term population-level tuberculosis disease (TB) incidence in sub-Saharan Africa.Methods:We used a mathematical model to consider the effect of different assumptions about life expectancy and TB risk during long-term ART under alternative scenarios for trends in population HIV incidence and ART coverage.Results:All the scenarios we explored predicted that the widespread introduction of ART would initially reduce population-level TB incidence. However, many modelled scenarios projected a rebound in population-level TB incidence after around 20 years. This rebound was predicted to exceed the TB incidence present before ART scale-up if decreases in HIV incidence during the same period were not sufficiently rapid or if the protective effect of ART on TB was not sustained. Nevertheless, most scenarios predicted a reduction in the cumulative TB incidence when accompanied by a relative decline in HIV incidence of more than 10% each year.Conclusions:Despite short-term benefits of ART scale-up on population TB incidence in sub-Saharan Africa, longer-term projections raise the possibility of a rebound in TB incidence. This highlights the importance of sustaining good adherence and immunologic response to ART and, crucially, the need for effective HIV preventive interventions, including early widespread implementation of ART. © 2013 Dodd et al.
antiretrovirus agent; Africa south of the Sahara; article; early intervention; Human immunodeficiency virus; Human immunodeficiency virus infection; incidence; infection risk; life expectancy; mathematical model; patient compliance; prediction; scale up; treatment outcome; tuberculosis; Africa South of the Sahara; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; HIV Infections; Humans; Incidence; Models, Theoretical; Public Health Surveillance; Tuberculosis
B&MGF, Bill and Melinda Gates Foundation; Wellcome Trust; MRC, Medical Research Council