Promising developments in HIV diagnostics
In the lead-up to Paris AIDS conference, WHO prequalifies first HIV self-test & Xpert viral load assay
The International AIDS Society (IAS) conference begins in Paris on July 23rd. Ahead of this major conference, WHO today announced pre-qualification of the first HIV self-test, as well as an automated, rapid molecular test for viral load.
The HIV self-test, the OraQuick ® HIV Self-Test (OraSure Technologies Inc.) uses oral fluid as a specimen and provides results in as little as twenty minutes. The WHO pre-qualification follows WHO recent guidelines that endorse the use of HIV self-tests, and has great potential to enhance HIV detection, especially among populations that are unlikely to seek care in traditional health services.
WHO also pre-qualified the Xpert® HIV-1 Viral Load assay by Cepheid Inc. This assay is an in vitro reverse transcriptase polymerase chain reaction assay for the detection and quantification of HIV type 1 (HIV-1) RNA in human plasma from HIV-1 infected individuals, using the automated GeneXpert Instrument Systems (Image). The new global 90-90-90 targets for HIV/AIDS require scaled-up HIV-1 viral load testing.
Globally, although over 6500 GeneXpert machines are now available for TB testing in over 100 countries, these systems are often underused because of high cost, restrictive algorithms, inadequate decentralisation, exclusion of the private sector from concessional pricing, and weak implementation of policies.
One potential solution is to expand access to tuberculosis testing, while simultaneously using the GeneXpert platform to test for other diseases of global health importance. Given the high co-prevalence of TB and HIV in many settings, and the need for greater integration of tuberculosis and HIV services, it makes sense to use the GeneXpert technology for HIV viral load testing.
In a recent study, we showed that existing GeneXpert systems that are primarily used for rapid tuberculosis testing can be leveraged successfully to implement this Xpert viral load assay in India. However, subsidised pricing, similar to that of the Xpert MTB/RIF cartridge, will be essential for scaled-up use in India and other LMICs.
WHO now encourages greater integration across disease areas, so that diagnostic devices with capacity to detect multiple diseases can be effectively used, especially in the context of universal health coverage. Better integration of TB and HIV testing is clearly an exciting area to realize the promise of this approach!