2.1. Preparation of the Framework
The basis for this Framework is the global TB strategy, which was approved by the World Health Assembly in May 2014 (9). It builds on the epidemiological analyses, health system assessments and strategic considerations that underpin the global strategy. Furthermore, the Framework is grounded in existing WHO guidelines for TB care, prevention and control.1 It does not contain any new recommendations on the diagnosis, treatment or prevention of TB but proposes adaptations of the existing recommendations and priorities for the epidemiological and health system conditions that are common in low-incidence countries.
WHO policy documents and guidelines and published literature were reviewed, and additional references were identified by experts in the field. A first draft was prepared by the WHO Global TB Programme, and a writing group consisting of 17 experts in the field was established (Annex 1), which reviewed the draft at a meeting in April 2014. They then revised the draft and added text and specific case studies. Definitions and the eight priority action areas were agreed upon during the meeting.
The writing group revised the document several more times before it was discussed by the WHO TB Strategic and Technical Advisory Group in June 2014. It was then circulated it to 30 country representatives and 26 representatives of research institutions and technical agencies and nongovernmental and civil society organizations that were invited to a global consultation in Rome, Italy, on 4–5 July 2014. Participants were asked to review the document and submit comments and suggestions, and group sessions were organized, corresponding to eight priority action areas, in order to obtain further input. The final document was reviewed by all contributors (Annex 1). Declaration of Interest forms were filled in by all contributors. People with links to or receiving grants from companies producing tools related to the priority actions acted as observers and did not contribute to preparation of the Framework.
Information on TB epidemiology and health systems in the Framework was derived from four sources: WHO's global TB database (23), a published survey of TB policies in the countries of the European Union (4), other published research and a survey conducted in all countries represented at the global consultation on elements of TB epidemiology that are not routinely reported to WHO but are available in national surveillance data sets (to various extents) and on existing policy and practice in TB care and control.
Preparation of the Framework was coordinated and funded by WHO and the European Respiratory Society.
2.2. Definitions of low incidence, pre-elimination and elimination
In this Framework, low-incidence countries are defined as those with a TB notification rate of < 100 TB cases (all forms) per 1 million population and year. This definition was proposed previously (17), while others have suggested different thresholds, such as < 200 per million (10) and < 160 per million (24). The threshold of < 100 per million is the same as the target global incidence rate for 2035, which corresponds to the goal of the global TB strategy to “End the global tuberculosis epidemic”. The principles and proposed actions of the Framework are relevant not only for countries that meet this low-incidence criterion but also for countries that are approaching the low-incidence threshold.
“Pre-elimination” is defined as < 10 notified TB cases (all forms) per million population and year, as proposed by Clancy et al. in 1991 (17). “Elimination of TB as a public health problem” is defined as < 1 notified TB case (all forms) per million population and year. In the WHO European Region, TB elimination was previously defined as < 1 sputum smear-positive case per million and thus focused on the most infectious TB cases (25). The ECDC has, however, proposed the above definition, which includes all forms of TB (18). Similarly, the US CDC defines elimination in the USA as < 1 case of TB, all forms, per million population (18,19).
In the above definitions, the TB notification rate is used rather than the estimated incidence, as both the health systems and TB surveillance systems in low-incidence countries are generally of high quality and the gap between the rate of notification of new cases and relapses and the true incidence rate is therefore small (1). Nevertheless, TB notification rates should always be evaluated in the context of the quality of the coverage of the TB surveillance system and, specifically, the likelihood of significant under-detection or under-reporting of TB. WHO guidance is available for this purpose (26).
