New childhood tuberculosis estimates double the number previously thought

Researchers from Brigham and Women's Hospital (BWH) and Harvard Medical School (HMS) in Boston have estimated that around one million children suffer from tuberculosis (TB) annually— twice the number previously thought to have tuberculosis and three times the number that are diagnosed every year. The researchers also estimated that around 32,000 children suffer from multidrug-resistant tuberculosis (MDR-TB) annually. These findings are published in The Lancet on March 23, 2014.

"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," explained Ted Cohen, MD, DrPH, HMS associate professor of Medicine in BWH's Division of Global Health Equity and co-senior author of this study. "Our estimate of the total number of new cases of childhood TB is twice that estimated by the WHO in 2011 and three times the number of child TB cases notified globally each year," said Cohen, who is also associate professor in the Department of Epidemiology at Harvard School of Public Health.

"TB in a child is recognized as a sentinel event; it tells us about ongoing transmission and missed opportunities for prevention," explained Mercedes Becerra, ScD, associate professor of Global Health and Social Medicine at HMS and co-senior author of the study. "Improved estimates are essential so that we can begin to understand the unmet need for pediatric TB treatment."

In order to obtain these estimates the researchers used several sources of publicly available data and devised a new method to correct for the chronic under-diagnosis that occurs in children, using conventional TB tests which were designed for and work best on adults.

The researchers used two models to estimate both the regional and global annual incidence of MDR-TB in children. Their findings indicate that around 1,000,000 children developed TB disease in 2010 and of those, 32,000 had MDR-TB.

These findings underscore the urgent need for expanded investment in the global response to TB and MDR-TB in children. "Our findings demonstrate that there is a need for improved methods for collecting data on childhood TB. A good starting place would be improved diagnostic methods for children and more systematic collection of information on how many children are suffering with this disease," explained Helen Jenkins, PhD, HMS instructor in BWH's Division of Global Health Equity and lead statistician on the project.

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This research was supported by the U.S. National Institutes of Health (U54GM088558, K01AI102944, R01AI097015), the Helmut Wolfgang Schumann Fellowship in Preventive Medicine at Harvard Medical School, the Norman E. Zinberg Fellowship at Harvard Medical School, and the Doris and Howard Hiatt Residency in Global Health Equity and Internal Medicine at the Brigham and Women's Hospital.

Brigham and Women's Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare. BWH has more than 3.5 million annual patient visits, is the largest birthing center in New England and employs nearly 15,000 people. The Brigham's medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in patient care, quality improvement and patient safety initiatives, and its dedication to research, innovation, community engagement and educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Biomedical Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human diseases, more than 1,000 physician-investigators and renowned biomedical scientists and faculty supported by nearly $650 million in funding. For the last 25 years, BWH ranked second in research funding from the National Institutes of Health (NIH) among independent hospitals. BWH continually pushes the boundaries of medicine, including building on its legacy in transplantation by performing a partial face transplant in 2009 and the nation's first full face transplant in 2011. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies and the Women's Health Initiative. For more information and resources, please visit BWH's online newsroom.