23 Mar, 12 | by BMJ
Of the 9.4 million new tuberculosis (TB) cases diagnosed each year, approximately 5% are multidrug resistant (MDR). This World TB Day there is an emphasis on children, which is long overdue. Until now, children have largely been excluded from discussions and advances in tackling TB.
This neglect means the true number of children affected by the disease is unknown. The newest estimate is that approximately half a million children have TB, with 70,000 dying each year. This estimate is a foundation on which to build a national and global commitment to improve the rates of diagnosis and treatment of TB in children.
Part of the reason why it has been so hard to get accurate data is that diagnosing TB is harder in children than in adults. The usual diagnostic test of sputum microscopy is not ideal as getting an adequate sample, especially from small children, is difficult. Also children are more likely to have paucibacillary disease (similar to HIV patients) reducing the sensitivity of sputum microscopy. Although recent advances in diagnostics have had an impact on the adult population the value of the newer tests for children is largely unknown.
It is important that children are considered from an early stage in the development of new diagnostics. The ideal test for children would be one that does not rely on obtaining sputum and is able to detect extrapulmonary disease. The announcement this year of increased funding into biomarker development omitted investigations for paediatric cases. One of the barriers to including children in research has been the lack of a diagnostic gold standard available for children. This has been addressed with the publication, this World TB Day, of expert consensus statements for diagnostic research criteria in children. But for this to have any impact it needs to be adopted by the funders and developers of TB diagnostics.
A further ray of hope for children affected by TB is the upcoming WHO report on research and development (R&D), financing, and coordination, which will call for the establishment of a binding convention for R&D with defined financial contributions from all governments. The current commercial R&D model is driven by the promise of high prices once products reach the market. The needs of TB patients and paediatric TB patients in particular will never be adequately served by this system, which relies on large profit margins. The call for alternative mechanisms and public leadership is long overdue.
The current treatment of TB in children is inadequate. In 2010, WHO issued rapid advice for the treatment of children with increased dosages for all major first-line drugs. But the lack of appropriate fixed dose combination (FDC) tablets to fulfil these recommendations has delayed their implementation and meant that very few children globally have benefitted from this change. WHO is working on releasing the ideal dose combination for new FDCs – but the process has been slow and as yet there is still no recommendation.
The situation for children with drug resistant TB (DR-TB) is even more complex. The difficulty in obtaining sputum samples for culture (used to diagnosis DR-TB) means that it is under-diagnosed with long delays in starting treatment. Once on DR-TB treatment, the drugs are not adapted for use in children and correct dosages present significant challenges for care givers. The work of global groups on developing and deploying evidence-based strategies to prevent child deaths from drug-resistant tuberculosis needs to be supported. Despite the difficulties and concerns faced by physicians treating children with DR-TB, the little evidence there is shows they can have better outcomes than adults.
It is important that this spotlight on children is not just for one day and that they remain “out of dark” with access to quality diagnosis and treatment. Lets ensure that the curse of TB does not extend beyond their life time.
Grania Brigden is the TB advisor for the MSF campaign for access to essential medicines.