Screening

Screening algorithms for children are listed in Annex 5.

Children 0 to < 15 years with a close contact with TB

Any of the following screening algorithms can be used:

Fig. A.5.1 Screening with symptoms (page 90)

Fig. A.5.2 Screening with CXR (page 91)

Children living with HIV should be followed up closely in the health-care system and should be screened for TB at every routine contact with an HIV care provider, at a health facility or in the community. Given the high risk of progression to TB disease and the high mortality rate, combined symptom screening should also be done at every contact with the health-care system, including events such as vaccination days, maternal health appointments, at nutritional screening and at food support programmes.

There are currently inadequate data to extrapolate use of CXR, CRP or mWRDs as screening tests in adults to children < 10 years living with HIV. Tests for TB infection are not useful for TB screening (see also 6.2.4).

Children living with HIV have a high risk of rapid progress to severe disease and death if a diagnosis of TB is missed. A child with HIV infection is 3.5 times more likely to progress to TB disease than a child who is HIV-negative (39). An estimated 16% of paediatric deaths from TB are among HIV-positive children, resulting in 36 000 deaths annually (2). It is for this reason that WHO strongly recommends that children with HIV be screened for TB.

Contact screening can be difficult. Once the contacts of a TB patient have been identified, they should be screened for TB symptoms and/or undergo CXR, followed by appropriate diagnostic evaluation (4, 5). Tracing of household contacts usually identifies many close contacts who are eligible for screening and TPT; however, it is expensive and time-consuming for health-care workers to identify the contacts of all known TB patients.

As for adults, tuberculin skin tests and interferon-g release assays should not be used to screen for TB disease in children (12, 34), as these tests cannot distinguish TB infection from TB disease and cannot predict who will progress to TB disease. Both tests may be influenced by mechanisms unrelated to TB infection and give false-negative or false-positive results. The role of these tests in decision-making for TPT is discussed elsewhere (4, 5).

mWRDs are not currently recommended for screening for TB disease in children < 15 years.

Child contacts are at high risk of TB disease, and the risk varies substantially by age. Newborn infants are at particularly high risk of infection with TB if the mother had untreated TB disease when they were born. Apart from the risk of exposure because of close proximity to adults in a household with TB, children < 5 years who are infected with TB have a 19% chance of progression to TB disease within 2 years (39). Most paediatric mortality occurs in this age group, with 80% of paediatric deaths from TB occurring in children < 5 years (40).

It is estimated that, in 2019, approximately 1.2 million children under 15 years of age fell ill with TB, and 230 000 died of TB (2). In about 56% of the 1.2 million patients, TB was not diagnosed or reported, the proportion being highest in children < 5 years of age (65%). The symptoms of TB are underrecognized in children because they are less specific and overlap with those of common childhood diseases, often leading to delayed diagnosis. Children are more prone to extrapulmonary forms of TB, which may challenge timely detection.

The algorithms for screening children are listed in Fig. A.5.1-A.5.6 in Annex 5.