You are here:

The Union takes action on the “Fourth 90”

Published on


By Prof Anthony Harries, Senior Advisor

Prof Anthony Harries

National TB Programmes aim to diagnose and treat patients who have developed tuberculosis (TB), with successful completion of anti-TB treatment being the yardstick to judge performance. Good progress has been achieved, with the latest figures showing a global treatment success rate of 85%. Long-term studies, however, all point to significant on-going morbidity after treatment has been successfully completed, which in turn is associated with a higher risk of death compared with people who have never had TB.

In 2016, The Union along with colleagues from Imperial College, London, and Columbia University, New York, drew attention to this issue from a disease programme perspective [1]. They argued for a better understanding of the burden of respiratory disability at the end of anti-TB treatment as well as better linkage between TB programmes and respiratory medicine services to assist those people still suffering from on-going pulmonary dysfunction.

In 2019, The Union took the argument further. The Stop TB Partnership several years earlier had launched the three “90-(90)-90” diagnostic and treatment targets to reach and treat at least 90% of all people with TB, including 90% of key populations, and achieve 90% treatment success for all people diagnosed with TB. Given not only the pulmonary disability that persists after anti-TB treatment but the long-term adverse events from treatment (such as deafness from aminoglycosides), on-going determinants (such as cigarette smoking) and associated co-morbidities (such as HIV infection and Diabetes mellitus), The Union proposed a “Fourth 90”. This target states that 90% of all people successfully completing treatment for TB can have a good health-related quality of life [2]. This “Fourth 90” for TB aligns perfectly with the “fourth 90” proposed for HIV/AIDS, both of which focus on person- and family-centred services to improve the quality and delivery of care. Implicit in this new proposed target is the need to routinely identify disability, TB-risk determinants and co-morbidities after anti-TB treatment has been successfully completed.    

In 2021, The Union working with National TB colleagues in China, and supported by the Johns Hopkins Centre for Tuberculosis, Baltimore, studied the feasibility of conducting post-TB assessments at the end of anti-TB treatment under routine programmatic conditions [3]. The study, undertaken in five TB clinics in China, demonstrated that such assessments were feasible without additional resources. There was substantial on-going morbidity with continuous symptoms in half of the people, functional disability in 20% (defined as a poor six-minute walking test), diabetes mellitus in 20% and cigarette smoking in 10%. Recommendations were made to perform these assessments not only at the end of anti-TB treatment but at the start of treatment as well, and ensure that those needing further care and support, such as pulmonary rehabilitation for pulmonary disability, actually received it.

This year, The Union with Chinese National TB colleagues, the Johns Hopkins Centre for Tuberculosis and supported by the Special Programme for Research and Training in Tropical Diseases, Geneva, has started to assess whether these recommendations can be implemented. The study, which is taking place in ten clinics in China, will determine such comprehensive assessment and care is possible within the routine setting.

The Union’s mantra is “Know, Share, Act”. Work within the routine programmatic setting to assess and care for disability, risk determinants and co-morbidities at the start and end of anti-TB treatment is an example of innovative operational research which aims to give patients not only a cure for TB but a good health-related quality of life.


  1. AD Harries et al. Int J Tuberc Lung Dis 2016; 20: 1010-1013. Doi: 10.5588/ijtld.16.0277.
  2. AD Harries et al. Int J Tuberc Lung Dis 2019; 23: 1253-1256. Doi: 10.5588/ijtld.19.0471.
  3. Y Lin et al. Trop Med Infect Dis 2021; 6: 164. Doi: 10.3390/tropicalmed6030164.