New estimates show that as many as 32-thousand kids worldwide are getting infected each year with a drug-resistant strain of tuberculosis. 

A new study by U.S. researchers found that overall, as many as one-million kids become sick with TB each year. 

That's about twice the number previously thought.  And of those, only a third of the cases are ever diagnosed. 

Tuberculosis typically attacks the lungs and it's spread through the air when infected people cough. 

The findings are being published in the "Lancet" to commemorate World TB Day on Monday.