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 Sunday in the Lancet.
The findings, published as part of a special theme issue of Lancet to commemorate World TB Day on March 24, 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.
"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.
For decades, researchers had largely ignored tuberculosis infections in young children, in part because children are less likely to transmit the disease than adults.
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.