Antiretroviral therapy is the principal cause of tuberculosis decline in southern and eastern Africa

Abstract

The incidence of tuberculosis (TB) in southern and eastern Africa was driven sharply upwards during 1980s and 1990s by coinfection with Mycobacterium tuberculosis and the human immunodeficiency virus (HIV). Although drug treatments for TB infection (isoniazid preventive therapy) and disease (combinations of TB drugs) can reduce TB incidence if implemented effectively, we find that antiretroviral therapy (ART) given to people with HIV infection was strongly and systematically associated with the accelerated decline of TB in 12 of the worst affected African countries between 2003 and 2016. Inferring that ART was a significant cause of TB decline, ART prevented approximately 1.88 {+/-} 0.23 million HIV-positive TB cases, or 15.7 {+/-} 1.9 percent of the total number expected. There is no evidence that drug treatment of TB infection (IPT) or disease (combination chemotherapy) played more than a minor role in accelerating TB decline after 2003. In these 12 countries, over the period 2003-16, ART made a major contribution towards achieving international targets for the reduction of TB incidence.\n\nSignificanceTuberculosis (TB) is still the leading cause of death from a single infectious agent. To cut the TB incidence rate by 80% between 2015 and 2030, in line with the WHO End TB Strategy, demands a five-fold increase in the rate of decline worldwide, from 2% to 10%/year. We find that the reduction in TB incidence rate in 12 African countries, at up to 8%/year, is due mainly to the expanded provision of antiretroviral therapy (ART) to people living with HIV, rather than to improvements in the treatment of TB infection and disease. ART should remain central to TB control where rates of TB-HIV coinfection are high, but new efforts are needed to maximize the direct benefits of treating TB infection and disease.