Operational Handbooks

It is important to exclude TB disease before initiating TPT. A clinical algorithm based on screening for symptoms of TB, history of contact with a person with TB, HIV status, age, TB infection test results and abnormal findings on CXR is recommended (15). Figure 3.4 shows an algorithm applicable to children aged under 5 years with and without HIV, and children and adolescents aged 5 years and over.

Children aged under 5 years who are household contacts of people with bacteriologically confirmed TB have a significantly higher risk of acquiring TB infection and progressing rapidly to TB disease. Children aged under 2 years are also at particularly high risk for severe and disseminated forms of TB with very high risk of morbidity and mortality. TPT is strongly recommended in all TB household contacts aged under 5 years once TB disease is ruled out.

Children and adolescents living with HIV are 8–20 times more likely to develop TB disease than those without HIV infection and should be prioritized for systematic evaluation and TPT in all settings (15, 46). Despite major progress in access to and effectiveness of ART, TB is the most frequent cause of acquired immunodeficiency syndrome (AIDS)-related deaths worldwide (47).

The WHO consolidated guidelines on tuberculosis (28) and the WHO operational handbook on tuberculosis (15) identify two broad at-risk child and adolescent populations that need systematic assessment for eligibility for TPT:

TB infection (previously called latent TB infection) is defined as a “state of persistent immune response to stimulation by M. tuberculosis antigens without evidence of TB disease” (15). The number of people worldwide estimated to have M. tuberculosis infection is 1.7 billion. Further, 7.5 million children aged under 15 years are estimated to be infected with TB every year (11).

Despite its safety, BCG is an attenuated live vaccine (M. bovis BCG). Contraindications include:

• pregnancy;
• people living with HIV but not on ART, or on ART but not immunologically stable;
• people with other forms of immunosuppression (e.g. candidates for organ transplants, people on immunosuppressive therapy).

This chapter describes strategies for the prevention of TB in children and adolescents. It covers BCG vaccination, TPT and TB infection prevention and control. This chapter relates to the section of the pathway highlighted in blue in Figure 3.1.