Next Generation Tests for Latent Tuberculosis Infection
A third of the world's population is estimated to be infected with Mycobacterium tuberculosis, the bacterium that causes Tuberculosis (TB). The vast majority of these infections are asymptomatic and not infectious (latent tuberculosis infection, LTBI), but these infections can re-activate and cause disease.
Blood and skin tests are available to identify people with LTBI, but they have only limited use in predicting which of these people will become ill. If we were able to identify and treat individuals with LTBI at the highest risk of developing symptoms, we could focus treatment on the people who would benefit from it the most.
The Next Generation Study was designed with three main aims:
- To assess the value of new blood tests ("fourth generation Quantiferon tests") in detecting LTBI in people who are at high risk due to contact with a person with TB disease, and the ability of these tests to monitor whether treatment for latent infection is succeeding. These new tests have not yet been evaluated in clinical practice, so their usefulness in identifying people at highest risk of TB disease and monitoring treatment is unknown.
- To investigate their accuracy for detecting TB infection in people with active TB disease.
- To estimate the risk of infection with TB during the annual Hajj and Umrah Pilgrimages by testing pilgrims before and after their journey to Saudi Arabia. Mass gatherings may encourage the spread of infectious diseases, however, the risk of TB infection during the Hajj has not been reliably measured.
An addition sub-study was added to enhance investigation of a TB incident at a London School. The purpose was to evaluate the clinical utility of next generation tests and other promising technologies for diagnosing LTBI and enhance TB screening among a younger age group (range: 11 – 15 years) in the context of a rapidly evolving high yield TB outbreak. This sub-study also aimed to explore associations between infection status and epidemiological markers of exposure to TB or transmission.
Study Sample Size: 2,000 participants.