Book traversal links for 5.3.1. Identifying children who should be treated for multidrug-resistant and rifampicin-resistant TB
Based on modelling estimates, between 25 000 and 32 000 children and young adolescents aged under 15 years develop MDR-TB disease annually (110). When treated, outcomes of children with MDR/RR-TB are good, with favourable outcomes in 78% (111) and over 90% in some cohorts (112). Despite these good outcomes, relatively few children are diagnosed and treated for MDR/RR-TB each year, with only 12 220 starting treatment between 2018 and 2020 (11% of the United Nations General Assembly High-level Meeting target of 115 000) (1, 9). Most deaths among children with TB are in those who are not treated (17). It is critical, therefore, to ensure timely and appropriate identification, diagnosis and treatment of MDR/RR-TB in children and adolescents.
Contact investigation and screening of child and adolescent contacts of infectious MDR/RR-TB source cases are essential for the rapid diagnosis of children with MDR/RR-TB disease and for prompt initiation of treatment (113). Evaluation of children who are contacts of people with MDR/RR-TB and diagnosis of DR-TB in children and adolescents are discussed in Chapter 4.
Children with clinically diagnosed or bacteriologically confirmed MDR/RR-TB should be treated with a WHO-recommended regimen. Bacteriologically confirmed MDR/RR-TB is based on identification of M. tuberculosis from a specimen from the child or adolescent by molecular or culture-based methods, along with demonstration of at least rifampicin resistance with a genotypic or phenotypic DST. Treatment of children with confirmed MDR/RR-TB should be based on the demonstrated DST results from their isolate (if available).
A clinical diagnosis of MDR/RR-TB can be made based on a clinical diagnosis of TB (TB disease without bacteriological confirmation) and either exposure to a known case of MDR/RR-TB or presence of other risk factors for MDR/RR-TB (child treated previously for TB or exposed to a source case who died from TB or failed TB treatment). Strain concordance between children and their adult source cases is around 83% for isoniazid and rifampicin susceptibility, meaning children are very likely to have TB with the same resistance pattern as their most likely source case (83). Therefore, children with clinically diagnosed MDR/RR-TB should initiate treatment for MDR/RR-TB without delay, while all efforts to confirm the diagnosis by bacteriological testing should be made. Treatment of children and adolescents with clinically diagnosed MDR/RR-TB should be guided by the DST results and the history of exposure to TB medicines of the most likely MDR/RR-TB source case.
If a culture from the child or adolescent ultimately is positive for M. tuberculosis and demonstrates MDR/RR-TB, they should be treated according to the DST of their isolate. If a child or adolescent is started on treatment for clinically diagnosed MDR/RR-TB treatment and subsequently has a culture that shows drug-susceptible TB, their treatment can be switched to that for drug-susceptible TB; this is expected to be an uncommon occurrence. If a child or adolescent with clinically diagnosed MDR/RR-TB has a negative culture, the child should complete the originally prescribed course of second-line treatment; they should not stop treatment or switch to drug-susceptible TB treatment.
Improving case-finding of (especially) young children with MDR/RR-TB is critical to reduce the risk of poor outcomes.