Scaling-up symptom-agnostic, community-wide screening toward global tuberculosis elimination: opportunities, challenges, and lessons from history.

There has been little change in global tuberculosis (TB) incidence in the 21st century. Although case notification has increased, millions of people with TB each year remain unreached. Recently there has been increased recognition that many people with undiagnosed, potentially infectious TB do not experience or report TB symptoms. Symptom-agnostic screening (e.g., by chest X-ray) can effectively identify such forms of TB. Although this activity is increasing globally and is beneficial to individuals screened, current levels fall far short of what is needed to impact transmission and population-level prevalence. A significant scale-up of symptom-agnostic screening across communities is required to improve treatment coverage and interrupt transmission. Although there are major political, financial, and health system challenges to undertaking such scale-up this is not without precedent. In the mid-20th century, in many countries that now experience a low TB burden, population-level chest X-ray screening was successfully undertaken and contributed to the decline in TB. In this article, we explore the challenges and opportunities that face countries wanting to scale-up symptom-agnostic screening and reflect on important lessons from the past.