TUBERCULOSIS UPDATES 2018
SERIES EDITORS: CHI CHIU LEUNG, CYNTHIA B E CHEE AND YING ZHANG
Tuberculosis updates 2018: Innovations and developments to
drug resistance diagnosis, latent tuberculosis
infection, treatment, vaccine.
The 2013 tuberculosis (TB) review series ‘Tuberculosis:
Current state of knowledge’ highlighted important gaps
in our existing knowledge on the complex interactions
between the pathogen and the host. We also detailed
major limitations in current control strategies.
then, there have been major developments in new
diagnostic tools and drugs/regimens for TB and latent
TB infection (LTBI), some of which have modiﬁed clin-
ical practice in both high- and low-burden countries.
In 2014, the World Health Assembly approved the ‘End
TB Strategy’, which set ambitious targets to achieve a
95% reduction in TB death and 90% reduction in TB
incidence rate by 2035.
To consolidate developments
and to meet the upcoming challenges, we have invited
a panel of international experts to critically re-examine
the relevant issues in a new series of themed reviews
focused on TB.
Despite over two decades of effort to ﬁnd and treat
infectious sources, there were still an estimated 10.4
million incident TB cases with 1.7 million deaths in
The annual decline of TB incidence remained at
around 2%, not much higher than the annual decline
of TB mortality of 1.71% in the United Kingdom in the
Resistance has also
emerged to most of the medications used to treat TB,
and the spread of multidrug-resistant (MDR) and
extensively drug-resistant (XDR) TB is threatening TB
control in many high-burden areas.
Against this back-
ground, there is a need to critically examine how we
can turn the vision of the End TB Strategy into reality.
Pursuing social protection, universal health coverage
and optimizing the use of new tools from the develop-
ment pipelines are necessary to achieve the priority tar-
gets of over 90% treatment coverage, treatment success
rate and preventive treatment coverage, and accelerate
the annual decline of TB incidence from 2% to 10% in
the coming decade. With the current estimate that one
quarter of the global population has been infected with
the tubercle bacillus,
critical breakthroughs in either
the screening and treatment of LTBI or the develop-
ment of new TB vaccines are indispensable to further
accelerate the annual decline of TB incidence to 17%
A high burden of LTBI is observed in rising elderly
populations in many Asia-Paciﬁc areas. This is largely
as a result of the heightened transmission arising from
the high TB incidence that peaked alongside rapid
urbanization in the last century.
Older people often
have a TB incidence several fold higher than younger
people in these areas.
With frequent co-morbidities,
TB in older people is often more difﬁcult to diagnose
and treat, posing a critical challenge in TB control.
Wing Wai Yew et al. will discuss the epidemiological,
clinical and mechanistic perspectives of TB in older
people, highlighting the colliding epidemics of smok-
ing, diabetes mellitus and TB, and how unravelling the
underlying mechanisms might potentially help to pre-
vent and better manage TB in this group.
Vaccines are often regarded as a ﬁrst-line tool in
controlling infectious diseases because they are more
readily applied on a population scale. However, the
existing Bacillus Calmette–Guerin (BCG) vaccine gives
only partial and variable protection against pulmonary
TB, the major source of infection, in adults.
Zhu et al. will highlight the challenges in the develop-
ment of new TB vaccines. As natural infection by the
tubercle bacillus fails to prevent reinfection,
inactivation or attenuation of the organism is unlikely
to produce a fully protective vaccine. However, quite a
number of candidate vaccines developed using new
approaches and/or delivery vectors have entered differ-
ent phases of clinical trials. Slow but steady progress
has also been made to discern the complex immuno-
logical mechanisms underlying vaccine protection.
Hopefully, suitable immunological correlates could be
identiﬁed to serve as biomarkers or surrogate end
points for selecting promising candidates for further
advancement in the development pipeline, thereby
minimizing the need for large and protracted clinical
trials using disease as the primary end point.
Delia Goletti et al. will review efforts to identify bio-
markers for disease development, treatment response
and outcome. Similar to immunological correlates, bio-
markers with good predictive power on a group basis
may circumvent the need to use disease or failure/
relapse as primary end points in protracted clinical tri-
als in new drug or regimen development for either
LTBI or active TB disease. Biomarkers with high predic-
tive power on an individual basis will be needed to
inform clinical decision on who, when and how to treat
As humans are the predominant hosts for Mycobac-
terium tuberculosis complex, selection pressure from
clinical use of TB drugs necessarily accounts for the ini-
tial emergence of drug resistance associated with vari-
ous naturally occurring chromosomal mutations.
However, most of the MDR-TB cases now arise through
secondary transmission of drug-resistant strains
© 2017 Asian Paciﬁc Society of Respirology Respirology (2018) 23, 356–358