Tuberculosis (TB)

WHO guidelines on the management of latent tuberculosis infection launched today

A new frontier in diagnosing and treating latent tuberculosis infection

Barcelona | 28 October 2014| For the first time, the World Health Organization has issued new guidelines on testing, treating and managing latent TB infection (LTBI) in individuals with high risk of developing disease. It is estimated that about one-third of the world's population has latent TB, which means people have been infected by TB bacteria but do not show symptoms of TB and cannot transmit the disease. People infected with TB bacteria have a lifetime risk of 5-10% falling ill with TB. However the risk is higher in persons with compromised immune systems, such as people living with HIV, patients with certain clinical conditions such as end stage renal stage or undergoing transplantation and patient with silicosis. Reactivation of latent TB significantly contributes to the TB burden particularly in low incidence countries. Currently available preventive treatment regimens can prevent TB with an efficacy ranging between 60 to 90%.

“Prevention of TB and the management of latent TB is one of the key elements of the new END-TB strategy of WHO to be pursued primarily in all low-incidence countries”, says Dr Mario Raviglione, Director of the Global TB Programme, WHO.

The new guidelines will provide public health approach guidance on evidence-based practices for testing, treating and managing LTBI in individuals with the highest risk of progression to active disease. “The new guidelines respond to the request of several Member States for a clear WHO guidance and provide the framework for the development of national guidelines for the management of latent TB” said Dr Haileyesus Getahun, WHO Coordinator for TB/HIV and Community Engagement. The adaptation of the policy need to consider available resources, epidemiology of TB including intensity of transmission, the health-care delivery system of the country, and other national and local determinants. “The guidelines primarily target high-income or upper middle-income countries with an estimated TB incidence rate of less than 100 per 100 000 population because they are most likely to benefit from the guidelines due to their current TB epidemiology and resource availability” added Dr Getahun. These criteria are currently met by 113 countries.

Selecting those who should be tested is critical

The guidelines recommend that systematic testing and treatment of LTBI should be performed in people living with HIV, adult and child contacts of pulmonary TB cases, and patients with the following clinical conditions: initiating anti-tumour necrosis factor treatment, receiving dialysis, preparing for transplantation, and being affected by silicosis). In addition, systematic testing and treatment of LTBI should be considered for prisoners, health-care workers, immigrants from high TB burden countries, homeless persons and illicit drug users.

Standards for testing and treatment were defined

The guidelines recommend that either tuberculin skin test or interferon gamma release assays can be use to test for latent TB in in high-income and upper middle-income countries with estimated TB incidence less than 100 per 100 000. “Currently, these are the only diagnostic tests available though they are both weak in predicting future development of TB among infected. Development of better diagnostic tools should be priority for research’ said Dr Alberto Matteelli, Medical officer from the TB/HIV and community engagement unit. Consistent with existing WHO recommendations, the guidelines reiterated that interferon gamma release assays should not replace tuberculin skin test in low-income and other middle-income countries.

Five treatment options are recommended for the treatment of LTBI in the guidelines: isoniazid daily for 6 or 9 months, the combination of rifapentine and isoniazid once a week for 12 weeks, the combination of rifampicin and isoniazid daily for 3-4 months, and rifampicin alone daily for 3-4 months.

Public health approach and resource allocation are essential

The management of LTBI requires a comprehensive package of interventions and public health measures. Establishment of functional and routine monitoring and evaluation systems that are aligned with national systems as well as appropriate recording and reporting tools is essential. Critical public health considerations for routine monitoring and evaluation include: initiation and completion of treatment, active surveillance of adverse events and the development of active TB during and after the completion of treatment for latent TB. Additionally, programme monitoring is needed to evaluate quality, effectiveness and impact. Creation of a conducive policy and programmatic environment, including the promotion of universal health coverage, is essential to facilitate the implementation of the recommendations. The LTBI management guidelines will be presented and discussed during the Union World Conference on Lung Health in Barcelona, Spain this week.

The LTBI management guidelines will be presented and discussed during the Union World Conference on Lung Health in Barcelona, Spain this week.