Controversies and unresolved issues in tuberculosis prevention and control: a low-burden-country perspective

Despite declining incidence in most high-income countries, tuberculosis shows no signs of disappearing in the near future. Although surveillance data from most Western European countries show relatively stable declines in the rate of tuberculosis over the past several decades, some have reported either an increasing rate or a decelerating pace of reduction in recent years. The burden of disease now disproportionately affects high-risk groups such as migrants, homeless persons, and prisoners. In view of the concentration of cases in urban areas and high-risk deprived groups, interventions that may not be efficient when applied to the general population may be highly cost effective when targeted at high-risk groups. In this article, we examine some controversial elements of tuberculosis prevention and control in low-burden countries and recommend issues for further research. In particular, we assess current evidence on the duration of protection by BCG vaccine, the screening of migrants and hard-to-reach groups, and the use of preventive therapy for contacts of cases of infectious multidrug-resistant tuberculosis. This analysis is presented from the perspective of low-tuberculosis-burden, high-income countries attempting to eliminate tuberculosis.