By Jeffrey Starke, MD, FAAP, liaison to the American Academy of Pediatrics Committee on Infectious Diseases
Despite the availability of inexpensive diagnostic tests, curative and preventive therapies, and the widespread use of the BCG vaccines, tuberculosis (TB) remains a major cause of morbidity and mortality among children, and its lack of control is one of our biggest public health failures.
A clinical diagnosis of childhood TB usually can be established using epidemiology (especially recent contact to a case subject), and clinical findings such as symptoms, radiography and a test for TB infection. However, TB in children is difficult to confirm microbiologically. Given the reliance on microbiologic tests for diagnosis and reporting cases in most high-burden countries, the majority of childhood TB cases are not diagnosed, or not counted if they are diagnosed clinically, leading to woeful under-counting of cases. Although microbiologic confirmation of childhood TB remains elusive, we have effective and safe regimens for treating TB disease and infection, and we know that early detection via contact tracing and treatment can prevent many cases of childhood TB.
In most high-income countries, childhood TB has decreased remarkably over the past 30 years. But this has not occurred in many low- and middle-income countries. In 2013, only 275,000 cases of childhood TB were reported by national TB programs1. Based on techniques used to estimate adult TB case numbers, the World Health Organization (WHO) estimated that there were actually 600,000 TB cases among children under 15 years of age, and 80,000 deaths from TB among HIV-negative children. (No estimates of mortality in HIV-positive children were given, but TB is a leading cause of death in HIV-infected children.) However, a review of 97 papers on multidrug-resistant TB in children used setting-specific estimates and TB incidence to estimate that there were 999,792 cases of childhood tuberculosis in 20102. Finally, sophisticated mathematical modeling techniques on reported TB data and local household structure have estimated that in just the 22 WHO high-burden TB countries in 2010, there were: 15,319,701 children cohabitating with a TB case; 7,591,759 children who became infected with Mycobacterium tuberculosis; and 650,977 children who developed TB disease3. Unfortunately, the actual case detection rate was estimated to be only 35%. Cumulative exposure in these 22 countries meant that 53,234,854 children were infected and at risk for developing TB disease in the near or distant future. Clearly, the burden of childhood TB infection and disease is enormous, many cases are never discovered, and few cases are being prevented.
Childhood TB has not received adequate attention from child health and TB programs. The child survival movement has not embraced TB because of the lack of accurate estimates of TB morbidity and mortality in children. TB services in most low- and middle-income countries, including access to drugs and diagnostic tests, are restricted to national TB programs so child health programs have paid little attention to the disease and its prevention. As a result, there has been little advocacy for child TB services on the part of pediatricians and child health experts. Because childhood TB is difficult to confirm with a sputum smear and children with TB are rarely contagious, many national TB programs have paid little attention to children. A common but misguided perception has been that giving infants a BCG vaccine and controlling adult TB in a population would be adequate to prevent childhood TB. As a result, effective prevention measures that are standard in low-burden countries, such as treatment of TB exposure and infection, have not been implemented in most high-burden countries. For several decades, WHO has recommended that children living in a household with a TB case who have symptoms should be evaluated for TB disease and those without symptoms should receive 6 months of isoniazid. However, this simple, safe and effective approach is rarely utilized in high-burden countries. Finally, there have been missed opportunities to correctly diagnose and treat children with TB in programs focused on other health problems of children who also are at risk for TB.
Over the past 30 years there has been an explosion of studies and science related to the diagnosis, treatment and prevention of childhood TB. In 2013, the WHO published a Roadmap for Childhood Tuberculosis4 detailing the ten essential steps for preventing children from dying from this treatable, preventable disease. The technology and means exist now to bring this roadmap to life. Actions and advocacy need to occur at the national and local levels. We know what to do; what we are lacking is the motivation, political will and coordination of services to do it.
World Health Organization. Global tuberculosis report 2014. World Health Organization, 2014. ISBN 978 92 4 156480 9.
Jenkins H, Tolman A, Yuen C, et al. Incidence of multidrug-resistant tuberculosis disease in children: systemic review and global estimates. Lancet. 2014; 383:1572-1579.
Dodd P, Gardiner E, Coghlan R, Seddon J. Estimating the burden of childhood tuberculosis in the twenty-two high burden countries: a mathematical modelling study. Lancet Glob Health. 2014; Aug;2(8):e453-9. doi: 10.1016/S2214-109X(14)70245-1. Epub 2014 Jul 8.
World Health Organization. Roadmap for Childhood Tuberculosis. World Health Organization, 2013. ISBN 978 92 4 150613 7.
This blog post is adapted from a previous publication:
Starke JR. Improving tuberculosis care for children in high-burden settings. Pediatrics. 2014; 134(4):655-657