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Tuberculosis

TB in Children (Global Perspective)

In many countries, tuberculosis (TB) disease is much more common than in the United States. The World Health Organization (WHO) estimates at least half a million children (less than 15 years of age) get sick with TB disease each year worldwide. However, it is difficult to estimate the true burden of TB among children globally, due to a lack of routine reporting of childhood TB by National TB Programs (NTPs), and the challenges of confirming the diagnosis of TB disease in children. The incidence of TB in children is influenced by various factors including:

The incidence of TB disease in the community;
The effectiveness of finding persons with TB disease and managing treatment;
Bacille Calmette-Guerin (BCG) vaccine coverage; and
The prevalence of risk factors for TB disease in children.

WHO estimates that childhood TB accounts for 6% of all incident TB cases worldwide, with most of the cases occurring in countries with a high rate of TB disease. Children can be diagnosed with TB disease at any age, but the most common is between 1 and 4 years of age. TB infection or TB disease in a child represents recent and ongoing TB transmission in their community.

TB Infection and TB Disease

TB is caused by a bacterium called Mycobacterium tuberculosis. TB bacteria are spread from person to person through the air. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks or sings. People nearby may breathe in these bacteria and become infected. Not everyone infected with TB bacteria becomes sick with TB disease. As a result, two TB-related conditions exist: latent TB infection (LTBI) and TB disease. The only sign of latent TB infection is a positive reaction to the tuberculin skin test (TST) or TB blood test. Tuberculin skin testing is considered safe in children, and is preferred over TB blood tests for children less than 5 years of age. In children, the TST is also useful as an aid in the diagnosis of TB disease. However, children with HIV infection who also have TB infection may not always have a positive TST result because they have a weakened immune system; a normal immune response is required to produce a positive TST reaction.

Once infected with TB bacteria, children (especially those children with risk factors for developing TB, for example, younger age, HIV, or other immune compromising conditions), are more likely to get sick with TB disease and to get sick more quickly. Treatment with isoniazid (isoniazid preventive therapy [IPT]) can reduce the chances of TB infection progressing to TB disease. This treatment is recommended by WHO for children less than 5 years of age who come in contact with someone with infectious TB disease, and for children with HIV infection.

Diagnosis of TB Disease in Children

WHO guidelines for diagnosing TB in children are similar to U.S. guidelines. WHO recommends the following approach for diagnosing TB in children outside the United States:

Obtain medical history (including history of any symptoms consistent with TB disease and history of being in contact with someone diagnosed with infectious TB disease)
Provide physical examination (including growth assessment)
Conduct tuberculin skin testing (TST)
Obtain and send specimens for laboratory testing for TB (bacteriological confirmation)-whenever possible
Conduct other diagnostic testing (e.g., chest x-ray) relevant for suspected pulmonary (lung) TB and suspected extrapulmonary (other parts of the body) TB
Provide HIV testing (in high HIV prevalence areas)

Key risk factors for TB in children are:

Household or other close contact with a person with infectious TB disease
Age less than 5 years
HIV infection
Severe malnutrition

(For more information, refer to Guidance for National Tuberculosis Programmes on the Management of Tuberculosis in Children)

TB and HIV Co-infection in Children

Worldwide, TB is one of the leading causes of death among people infected with HIV. HIV infection is common in children with TB in regions endemic for TB and HIV. Children with HIV are at a greater risk for TB infection and TB disease than children without HIV infection.

TB Treatment

TB treatment outcomes in children are generally good, provided treatment starts promptly. The response to TB treatment is poorer in children with HIV infection than in children without HIV infection.

In 2010, WHO revised its guidance regarding treatment of TB in children outside the United States. The revised guidance included revised recommendations for pediatric dosages of the four essential anti-TB medicines. (Refer to Rapid Advice: Treatment of Tuberculosis in Children for detailed information.)

TB Vaccine

BCG, or bacille Calmette-Guerin, is a vaccine that is given to prevent TB disease. It is most effective in preventing severe forms of TB disease, such as TB meningitis and disseminated TB, in infants and young children. BCG is not routinely used in the United States. However, many people born outside of the United States have been BCG-vaccinated. More information about BCG vaccine policies and practices globally can be found at the BCG World Atlas website.

In 2007, WHO revised its BCG vaccine recommendations for infants at risk for HIV infection and now recommends that children known to be HIV-infected, even if asymptomatic, should not be immunized with the BCG vaccine. (Refer to Revised BCG vaccination guidelines for infants at risk for HIV infection for more information.)