Childhood TB higher than WHO estimates: Study

Children developing tuberculosis (TB) every year in countries most affected by the disease is "25 percent higher" than the total number of new cases worldwide estimated by WHO in 2012, says a study.

Over 650,000 children develop TB every year in the 22 countries with a high burden of the disease (HBCs), but the World Health Organisation in 2012 estimated the total number of new cases worldwide at 530,000, say researchers at Britain's University of Sheffield. About 15 million children worldwide are exposed to TB every year, and roughly 53 million are living with latent TB infection, which can progress to infectious active TB at any time, according to the study.

"Our findings highlight an enormous opportunity for preventive antibiotic treatment among the 15 million children younger than 15 years of age who are living in the same household as an adult with infectious TB," said lead author Peter Dodd. "Wider use of isoniazid therapy for these children as a preventative measure would probably substantially reduce the numbers of children who go on to develop the disease." 

In contrast with standard estimates that are reliant on paediatric case reporting, which varies widely between countries, the researchers used mathematical modelling to estimate rates of infection and disease in children. It was based on country-specific data on household and population structure, and the prevalence of TB in adults.The model incorporated both social and epidemiological variables including the effects of age, BCG vaccination efficacy, and the effect of HIV infection.

The study appeared in the journal lancet Global Health.