Future Directions in Tuberculosis Diagnosis, Health News, ET HealthWorld

by Dr. Gautam Wankhede

Before the COVID-19 pandemic, India was facing another epidemic: tuberculosis (TB). According to the National Tuberculosis Elimination Strategic Plan (2017-2025), Tuberculosis kills about 4,80,000 Indians every year and more than 1,400 every day. The pandemic has reversed years of global progress in the fight against tuberculosis. The number of TB cases in India increased by 19% in 2021 compared to the previous year. India has the highest proportion of people in the world diagnosed with TB and drug resistant TB and the highest proportion of undiagnosed TB cases. While India has set 2025 as its goal to eliminate TB, to achieve this the country needs a 10% annual reduction in cases.

The success of TB control will depend on systematic monitoring of ongoing TB treatment, strong policies, wider access to rapid diagnosis and the provision of effective treatment.

Diagnosis of tuberculosis:
Access to TB testing is an essential first step in reducing disease transmission and appropriately managing those affected. Unlike COVID-19, a rapid test or self-test is not an option due to low accuracy. All serologic tests for tuberculosis are banned in India and are not used to diagnose tuberculosis. The tuberculin skin test (TST) remains the diagnostic intervention of choice in children. However, this is not entirely accurate. In addition, exposure to BCG vaccination can lead to a false positive reaction to TST, which can complicate decisions about prescribing treatment. Likewise, interferon gamma release assay (IGRA) tests are not preferred for diagnosis because they are very expensive.

Rapid molecular tests were introduced along with other traditional methods of microscopy and X-ray imaging. But the problem is that molecular diagnosis had a limited scope. Even after a huge surge, India conducted only 30L of tests (including positive and negative) in 2020, compared to 26L of positive cases estimated by the WHO that year. But today, India is very well prepared with over 3000+ new RT-PCR machines installed during COVID-19. These machines have a throughput up to 16 times higher than the traditional CB-NAAT machine. This means that India can now perform a higher volume of TB tests and faster.

The other problem is the detection of latent tuberculosis. Latent TB also known as inactive TB. It can turn into active TB if proper treatment or medication is not given at the right time. Therefore, treatment is important for the person with latent tuberculosis as it helps to control the spread of tuberculosis. The estimated global prevalence of latent tuberculosis is 33%, or one in three people. This means that even if we detect and treat those with active TB, those infected with latent TB will create a huge pipeline of new cases. Progression, detection and treatment of latent TB cases are important for TB control and reduce the burden of disease. Neither the TST nor the IGRA is useful in distinguishing between active and latent tuberculosis. But it looks like there’s a new test in sight that can be both inexpensive and accurate.

Tuberculosis treatment
The next problem is inadequate and inappropriate treatment of identified cases leading to increased burden of drug resistance. Although TB ​​is preventable and treatable, there are several challenges. One of them is the choice of treatment due to the very high prevalence of drug resistant tuberculosis in India. But manufacturers are now designing tests that can inform drug resistance of multiple drugs, right at the time of diagnosis. For example, 11% of new TB patients in India are resistant to isoniazid. Knowing this in advance, clinicians can treat patients more successfully. The Indian government’s efforts for Direct Benefit Transfer (DBT) to patients who complete their drug treatment is a great tool for adherence and can be a game-changer once diagnostic methods are strengthened.

Continued investment and research into new vaccines as well as drugs for both diseases is badly needed to achieve better results BCG is the only vaccine available against TB and confers significant protection during the In childhood, however, the protective efficacy of BCG against pulmonary tuberculosis in adults, which represents a greater disease burden, is highly variable.

In conclusion, there is an opportunity to leverage innovations in mass screening implemented as part of the pandemic response to close the gaps in TB screening and help control transmission of the disease. . The implementation of innovative TB screening strategies could improve access to screening among populations most at risk of contracting this disease.

Dr. Gautam Wankhede, Director of Medical Affairs, Mylab Discovery Solutions

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