“This technology can be scaled and decentralised to hotspots of infection in sub-Saharan Africa, to support the healthcare infrastructure” – Professor Ravi Gupta
Virus testing technology developed to work in Africa to diagnose HIV infections has proven new utility in speeding up diagnosis of COVID-19 infections in patients in hospital in Cambridge, leading to faster treatments while freeing up beds for other urgent operations. The COVIDx study at Addenbrooke’s Hospital compared the use of SAMBA II diagnostic machines with the standard RT-PCR test that takes 24 hours to deliver results and found a significant impact of the faster machines on how quickly the hospital could deal appropriately with patients.
Developed by University of Cambridge researchers in the spinout non-profit company Diagnostics for the Real World, the repurposed SAMBA II platform now offers hope for bringing fast and reliable COVID-19 testing to countries where medical infrastructure is under-developed for coping with the new pandemic. In low and middle-income countries lacking testing kits, reagents and extensive laboratory facilities, hospitals could quickly be overwhelmed as COVID-19 moves through the population. “This technology can be scaled and decentralised to hotspots of infection in sub-Saharan Africa, to support the healthcare infrastructure” said Professor Ravi Gupta of Addenbrooke’s Hospital, who led the recent research.
SAMBA II machines are specifically designed to work with robust, pre-mixed chemical reagents in conditions of high humidity, heat and dust, and are small enough to transport on a motorbike. Over 100 machines using the SAMBA platform are in operation in Malawi, Zimbabwe and Uganda for HIV detection.
The platform can be set up to detect any virus or bacterium whose DNA or RNA sequence is known. The machines perform a Simple AMplification-Based Assay, in which they detect and multiply tiny traces of a specific short length of the nucleic acid sequence, giving a positive or negative result for presence of the infecting organism.
Operating the machines is a simple process with one sample at a time per machine (from nose and throat swabs for SARS-CoV-2, or blood samples for HIV). Around 90 minutes to 2 hours later the results can be read out visually like a pregnancy test and can be electronically transmitted to a computer or mobile phone.
While these machines are not the answer to mass population testing, the rapid ‘point-of-care’ test allows patients (and staff) in a hospital or clinic to be triaged quickly the same day, either to receive urgent treatment, or to be discharged home or to social care settings.
In rural areas in African countries where it takes hours or days for patients to travel to clinics, the rapid diagnosis enables testing and treatment on the same visit. The SAMBA II machines (which cost around £20k) and reagent cartridges can be easily distributed to vulnerable hotspots such as district hospitals, and used by non-experts. “Our goal has always been to make cutting-edge technology so simple and robust that the SAMBA machine can be placed literally anywhere and operated by anyone with minimum training,” said Dr Helen Lee, CEO of Diagnostics for the Real World.
Prof Ravi Gupta concludes: “Now we have the data from the COVIDx study, we can trial the use of our point-of-care test in African countries for screening patients to prevent outbreaks in healthcare facilities”.
Listen in to Prof Ravi Gupta taking part on a panel of international experts in the BBC World Service radio programme ‘Coronavirus: The Evidence, Sub-Saharan Africa and testing’.