Tuberculosis (TB) infection is a state that is characterized by persistent immune response to stimulation by Mycobacterium tuberculosis (Mtb) antigens with no evidence of clinically manifest TB disease. It is estimated that about a quarter of the world’s population is infected with Mtb. Testing for TB infection increases the probability that individuals who are the target for TB preventive treatment (TPT) will benefit from such treatment.
The two currently available classes of tests – IGRAs and the tuberculin skin test (TST) – are indirect and require a competent immune response to identify people infected with TB.
WHO plans to update its guidance on use of IGRAs for the detection of TB infection. The aim of this update is to compare new (index) IGRAs with the IGRAs currently recommended by the WHO (reference tests) for the diagnosis of TB infection. Index IGRAs that will be evaluated may include, but not limited to: SD Biosensor’s STANDARD E TB-Feron ELISA (TB-Feron), SD Biosensor’s STANDARD F TB-Feron ELISA (FIA), Qiagen’s QIAreach QuantiFERON®-TB (QIAreach), bioMérieux’s VIDAS® TB-IGRA (VIDAS), and Oxford Immunotec’s T-SPOT.TB with T-Cell Select (T-Cell Select) assays.
The IGRAs that are currently recommended by the WHO for diagnosis of TB infection (reference tests) for the coming update include: Qiagen’s QuantiFERON-Gold (QFT-G), QuantiFERON-TB Gold In-Tube (QFT-GIT) and QuantiFERON-TB Gold Plus (QFT-plus), Oxford Immunotec’s T-SPOT.TB (T-Spot) and Beijing Wantai’s TB-IGRA (Wantai) assays.
To support this process, WHO is issuing a public call for data, appealing to national TB programmes, implementers, industry, researchers, manufacturers and other agencies to provide suitable evidence on the use of IGRAs for detection of TB infection.
The data will be essential to facilitate the process of WHO policy updates, scheduled for October 2024. Please send relevant data by 30th June 2024, to Alexei Korobitsyn at korobitsyna@who.int
For more information on the research questions which will be answered by the coming update see Annex 1.