As many as 32 000 children worldwide become
sick each year with a drug-resistant "superbug" strain of
tuberculosis, according to new estimates by US researchers that for the first
time quantify rates of this difficult-to-treat form of TB.
Overall, as many as 1 million children
become sick with TB each year, about twice the number previously thought, and
of these, only a third of the cases are ever diagnosed, the study found.
"A huge proportion (of children) are suffering and dying from TB
unnecessarily," said Helen Jenkins of Brigham and Women's Hospital's
Division of Global Health Equity, the lead statistician on the study published
on in The Lancet.
Read: Quick tests = fewer TB deaths
The findings, published as part of a
special theme issue of The Lancet to commemorate World TB Day, offer the
clearest picture yet of the global burden of tuberculosis among its youngest
victims, and for the first time estimate the burden of multidrug-resistant
tuberculosis or MDR-TB.
ignored in young children
"Despite children comprising
approximately one quarter of the world's population, there have been no
previous estimates of how many suffer from MDR-TB disease," said Dr. Ted
Cohen, also of the Harvard-affiliated Brigham and Women's Hospital, and a
co-author on the paper.
decades, researchers had largely ignored tuberculosis infections in young
children, in part because children are less likely to transmit the disease than
TB infections are especially hard to
diagnose in children because the infection looks different in children than
adults. The disease is caused by bacteria that typically attacks the lungs and
is often spread through the air when people who have an active infection cough.
Tuberculosis typically attacks the lungs and is spread through the air when
people who have an active infection cough.
Read: TB remains leading killer
"In kids, you are much more likely to
have TB disease in other parts of the body, not necessarily in the lungs,"
Jenkins said. Even when children do have TB in their lungs, there are fewer TB
pathogens present, "making kids with TB invisible" to current diagnostic
methods, she said.
To arrive at their estimates, Jenkins and
colleagues scoured publicly available databases and devised a way to correct
for chronic underreporting of TB in children. "What we found was that
whereas previous estimates for the total number of TB cases in kids were about
half a million, when you account for (underreporting) in your estimates, it's
more like 1 million children develop active TB disease every year," she
The World Health Organisation estimates
that 8.6 million people developed TB in 2012 and 1.3 million died from the
disease. According to the WHO, half a million people became sick with dangerous
superbug strains of tuberculosis in 2012, it estimates that up to 2 million
people worldwide may be infected with drug-resistant TB by 2015.
Read: Is TB a serious illness?
Keeping track of TB rates in children is
important for two reasons, Jenkins said. Firstly, children with drug-sensitive
forms of TB generally respond very well to treatment. Secondly, because TB
disease develops very quickly in children, often within weeks of exposure,
finding an infected child can offer key clues about TB transmission within a
"That's telling you you've got some
kind of system failure going on there," Jenkins said. She said the
findings illustrate the need for better methods of collecting data on childhood
TB, including better diagnostics and more systematic data collection.
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