study has revealed that there may be 650,000 annual cases of TB in children. In
reality, WHO has been closely involved in much of this recent research, as was
brought out in a podcast done by TB Alliance (Global Alliance for TB Drug
Development) in which Derek Ambrosino interviewed some of the leaders in
paediatric TB research, including the lead author of the study - Dr Peter J
Charalambos Sismanidis, of the WHO Global TB Programme, informed that, "Since
the end of 2012, when the first set of estimates was published in the 2012 WHO
Global TB Report, after reviewing all literature and synchronizing all
available data, we were actively looking for additional funding to move forward
our work of bettering those estimates, through alternative approaches that
would improve our understanding of the childhood TB disease burden. And this is
when collaboration with TB alliance and UNITAID funded STEP TB project
materialized around early 2013."
of the key products of this collaboration has been a global consultation on
disease estimation of childhood TB and quantification of the drug market size.
One objective of the consultation was to further develop analytical tools for
disease burden estimation. We commissioned work with a number of research
groups (and Peter's group was one of those) to think outside the box and come
up with alternative approaches to come up with improved estimates of the burden
of childhood TB. "
Brief recap of the Lancet study
study, funded by UNITAID and USAID, aimed to estimate the incidence of TB
infection and disease in children less than 15 years. Within a mechanistic
mathematical model, estimates of adult TB prevalence in 2010, in the 22 countries
with a high burden of the disease, were combined with aspects of the natural
history of paediatric TB. Household exposure and infection were also estimated,
accounting for the effects of age, BCG vaccination, and HIV infection.
the median number of children estimated to be sharing a household with an
individual with infectious TB was 15,319,701. The median number of MTB
infections in children was 7,591,759 and 650,977 children developed the
disease. The findings suggest that in 2010, 35% of paediatric cases of TB in
the 15 countries reporting notifications by age were detected. India alone is
predicted to account for 27% of the total burden of paediatric TB in the 22
countries. The predicted proportion of TB burden in children for each country
correlated with incidence, varying between 4% and 21%.
model has shown that the incidence of paediatric TB is higher than the number
of notifications, particularly in young children. Estimates of current
household exposure and cumulative infection suggest an enormous opportunity for
Peter J Dodd spoke about the strengths and weaknesses of the model used in this
main strengths are:
model does not use notifications in children (which we have good reasons to
believe are short of true incidence and are poorly understood), and
is a model with lots of stages along the way to disease, including exposure and
infection, and it allows to generate many more outputs. The weakness is that we
have to make many assumptions, each of which require some data that is
imperfectly known to the informant."
Cherise Scott, Head of paediatric TB programme at TB Alliance, stressed upon
the need for accurate estimates of paediatric TB burden to understand the
magnitude of the problem, as well as the location of the problem in order to
know where we need to work the hardest to ensure that appropriate treatment is
available for children suffering with TB. Understanding the magnitude of the
problem will also compel policy makers, donors and other decision makers to
invest resources in this area.
said that, "Understanding the burden of childhood TB is very complicated. We
tend to miss many cases because—children are not brought into the clinic, or
children are misdiagnosed for pneumonia and malnutrition. While physicians and
community workers often fail to check for TB when they come across a child who
has fever/cough/low weight, we also do not have a good confirmatory test for
clinical diagnosis of TB in a child. If we can improve in these areas, we will
be closer to having an accurate picture of paediatric TB burden."
people are now aware of childhood TB, many governments want to understand the
problem in their specific context and are willing to partner and work with
entities like the WHO and TB Alliance to improve their assessment and reporting
of childhood TB. This is a great first step to identifying and reaching as many
children affected by TB as we can, so that we can get them on treatment. TB is
a curable disease and if we find children exposed to, or infected with TB, they
can be treated and their lives can be saved."
of the major challenges in tackling childhood TB is to understand the scope of
the problem. Results of this study will be taken into consideration and will be
used for updating the estimates of childhood TB in the upcoming 2014 WHO Global
TB report. Additionally, more research is expected and needed in order to even
further define the paediatric TB landscape. Accurately quantifying the size of
the market and burden of disease among children is necessary to understand the
real demand for paediatric TB treatment and inform manufacturers' efforts.
Equally important is to understand the market dynamics that influence uptake and
appropriate use of products. All of this will benefit from better
epidemiological data in children.
Shukla, Citizen News Service (CNS)