Despite being both curable and preventable, tuberculosis (TB) remains a significant contributor to global morbidity and mortality. In 2021, approximately 10.6 million individuals were afflicted with TB, leading to 1.6 million deaths. While TB can be successfully treated, the weakest link in the global approach lies in its diagnosis. TB programs have long relied on sputum smear microscopy as the primary diagnostic test. However, microscopy has numerous drawbacks, including low sensitivity and an inability to identify drug resistance. It is not effective in individuals with TB and human immunodeficiency virus (HIV), in children, and in patients with extrapulmonary disease. Maintaining its effectiveness requires extensive quality assurance systems, and test success is based on skilled operators and high-quality specimens. Recent research published in Nature Microbiology underscores the advantages of adopting the tuberculosis diagnosis transformation recommended by the World Health Organization (WHO).
The study by Pie et al. underscores that, when compared to sputum smear microscopy, molecular testing offers significant advantages including greater accuracy, reduced diagnostic delays, and identification of drug resistance. The integration of rapid, decentralized molecular testing with implementation support to overcome delivery barriers results in approximately 50% more patients receiving a diagnosis. Although the WHO recommends molecular diagnostics as the preferred first-line testing approach, only 38% of all reported cases in 2021 underwent testing with a WHO-recommended rapid molecular diagnostic during the initial diagnosis. In 2023, the WHO introduced a new standard, the Universal Access to TB Diagnostics roadmap, which advocates for the use of a WHO-recommended diagnostic as the initial test for all patients with presumed TB, including those living with HIV, children, and individuals with extrapulmonary TB, in all facilities across all districts. This shift is already taking place globally, with Goa in India being the first state to transition entirely to molecular testing for TB, as reported by the Times of India (TOI).
The commitment of global stakeholders, as reflected in the WHO target product profiles, serves as a catalyst for innovation and collaboration in the field of TB diagnostics. It encourages the alignment of research endeavors with the specific needs outlined by the WHO, fostering a more coordinated and effective response to the challenges posed by tuberculosis.
In conclusion, the proactive adoption of the WHO target product profiles not only underscores the urgency of addressing gaps in TB treatment monitoring and optimization but also sets the stage for a transformative era in diagnostic development. By prioritizing precision and accessibility, these efforts promise to enhance the overall landscape of TB management, thereby achieving the goal of reducing the global burden of this disease.
References
- Pai M, Dewan PK, Swaminathan S. Transforming tuberculosis diagnosis. Nat Microbiol. 2023 May;8(5):756–9.
- Molecular testing to replace age-old sputum to detect TB. The Times of India [Internet]. 2023 Nov 20 [cited 2023 Nov 22].
- WHO releases updated Target Regimen Profiles for tuberculosis treatment and new Target Product Profiles for tuberculosis treatment monitoring and optimization [Internet]. [cited 2023 Nov 22].