By Claire Wingfield
It is estimated that of the nine million new cases of tuberculosis (TB) each year, one million occur among children under the age of 15. Yet advocacy for prevention, diagnosis, and treatment of TB in children has been largely absent from the global public health agenda. In fact, the true global burden of TB in children is unknown because of the lack of child-friendly diagnostic tools, and inadequate surveillance and reporting of childhood TB cases. National TB programs and research efforts have ignored TB in children for a variety of reasons, among them that children are less likely to spread disease. However, the stark reality is that children with TB infection today represent the reservoir of TB disease tomorrow.
If TB is going to be eliminated, research needs to address the unique aspects of childhood TB. Children are more susceptible than adults to advancing from TB exposure to infection and to disease, yet none of the current clinical trials evaluating new or existing drugs in TB disease include children. The reasons cited for not including children in drug trials are numerous, but they tend to range from insufficient funding to lack of childhood TB expertise to concern about confirming TB diagnosis. Despite this, we still have a moral obligation to more proactively address these challenges and include children in TB research to ensure that they also benefit from scientific advances.
Thanks in part to the efforts of TAG, childhood TB is finally getting some attention from the scientific community. Protocols are being developed for studies that would evaluate the safety and pharmacokinectics—how drugs are absorbed, distributed, metabolized, and eliminated in the body—of two TB drugs in infants and children. Institutions like the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. National Institute of Allergy and Infectious Diseases (NIAID) in collaboration with several academic institutions and an industry partner are taking the first steps to initiate TB treatment trials in children.
Confirming a TB diagnosis in a child can be very challenging and is therefore a major complication for pediatric TB treatment trials. Current methods of diagnosis using microscopy and culture produce mediocre results at best. But there has been some recent progress on improving diagnosis in children. In December 2010, the World Health Organization (WHO) recommended the Xpert MTB/RIF—a new rapid diagnostic test—be used in place of the most common TB diagnostic tests in cases of suspected HIV-associated and drug-resistant TB in adults. The Xpert MTB/RIF has the potential to significantly improve TB diagnosis and get patients onto appropriate treatment more quickly. At the time of the WHO’s announcement, there were no data on how best to use this new technology in children. However, in July 2011, the first study providing evidence that Xpert MTB/RIF was reliable in diagnosing TB in children was published. Hopefully, this one study will pave the way for more data-gathering to increase the number of children receiving timely and accurate TB diagnoses.
Given the historical and systematic neglect of children affected by TB, there is a need for urgent action from all who are committed to reducing the global burden of TB. New evidence must be generated on how best to prevent, diagnose, and treat TB in children. To that end, researchers must include children in high-quality basic, clinical, and operational research. Lastly, but most importantly, advocates and community members must continue to sound the alarm about the challenges of childhood TB and demand greater support and resources for these efforts.