The Incidence of Tuberculosis among Young Children is Higher than Reported

A study led by researchers from the Manhiça Health Research Centre (CISM) and ISGlobal estimates the incidence (number of new cases) of tuberculosis (TB) among children under three years of age that live in the community and concludes that many cases of pediatric TB are not detected, which is a serious problem particularly in countries with a high HIV prevalence like Mozambique. The results, published in the Pediatric Infectious Disease Journal, provide valuable information to efforts aimed at producing better estimates of global TB, a critical step to define public health policies. 

TB diagnosis among young children is challenging due to the lack of specific symptoms and the difficulty in obtainins samples for microbiological examination. For this reason, the true burden of the disease may be higher than the WHO estimates. In fact, Mozambique is listed by the WHO as a country with high TB burden although its reported case-detection rate is low (37%). 

The study recruited more than 13,000 children under three during one year with the aim of estimating the minimum community-based incidence of TB in Manhiça. It combined passive case detection and active case finding together with a series of standardized diagnosis tests for each suspected case. The results show that the incidence rate of pediatric TB is 470 out of 100,000 persons per year, although the authors point out that this is likely to be an underestimation.  This number is almost the double of reported estimates for the district, which shows that in this and other regions of Africa, a high percentage of children with TB are not diagnosed or not reported.  

The study also reveals the difficulty in diagnosing TB among HIV-positive children, given the overlap between symptoms. The authors point out that many children who die of diseases like malnutrition or respiratory infections may in fact have undiagnosed TB, and they conclude that TB control is crucial for improving child survival.   

Tuberculosis is caused by Mycobacterium tuberculosis and is preventable and curable with the adequate antibiotics. Despite this, it is second only to HIV/AIDS as the single infectious agent that causes the most deaths in the world (95% of these deaths occur in middle and low-income countries).

Reference:

López-Varela E, Augusto OJ, Gondo K, García-Basteiro AL, Fraile O, Ira T, et al. Incidence of Tuberculosis Among Young Children in Rural Mozambique. Pediatr Infect Dis J. 2015 Jul;34(7):686-92.