Where is tuberculosis transmission happening? Insights from the literature, new tools to study transmission and implications for the elimination of tuberculosis

Abstract

More than 10 million new cases of tuberculosis (TB) are diagnosed worldwide each year. The majority of these cases occur in low- and middle-income countries where the TB epidemic is predominantly driven by transmission. Efforts to 'end TB' will depend upon our ability to halt ongoing transmission. However, recent studies of new approaches to interrupt transmission have demonstrated inconsistent effects on reducing population-level TB incidence. TB transmission occurs across a wide range of settings, that include households and hospitals, but also community-based settings. While home-based contact investigations and infection control programmes in hospitals and clinics have a successful track record as TB control activities, there is a gap in our knowledge of where, and between whom, community-based transmission of TB occurs. Novel tools, including molecular epidemiology, geospatial analyses and ventilation studies, provide hope for improving our understanding of transmission in countries where the burden of TB is greatest. By integrating these diverse and innovative tools, we can enhance our ability to identify transmission events by documenting the opportunity for transmission-through either an epidemiologic or geospatial connection-alongside genomic evidence for transmission, based upon genetically similar TB strains. A greater understanding of locations and patterns of transmission will translate into meaningful improvements in our current TB control activities by informing targeted, evidence-based public health interventions.

Contemporary Concise Review 2018: Respiratory infections and tuberculosis

“…A targeted approach is therefore necessary to optimize the benefit versus risk ratio at the expense of reduced population coverage . Despite the higher risk of TB infection among household contacts, household transmission accounts only for a small portion of the overall transmission in the ongoing TB epidemic . The safety of rifapentine in pregnancy remains to be established even though no excess risks of foetal loss or congenital anomalies were observed among pregnant women inadvertently exposed to either isoniazid or isoniazid plus rifapentine in two clinical trials …”

Molecular epidemiology and drug resistance patterns of Mycobacterium tuberculosis complex isolates from university students and the local community in Eastern Ethiopia

“…Designing public health programs to decrease TB transmission among high step to lower TB incidence rates is an essential component of the public health program in Ethiopia. However, current epidemiologic tools such as contact investigations provide incomplete information about the primary drivers of TB transmission [ 3 ].…”

Defining adequate contact for transmission of Mycobacterium tuberculosis in an African urban environment

“…In future studies, we will evaluate the criterion validity of these factors by relating them to the presence, or absence, of tuberculous infection among social networks of tuberculosis cases. Moreover, since social mixing differs across cultures [49], these factors could be evaluated in other contexts and other populations, including from middle-and highburden countries.…”