A new type of COVID-19 testing strategy could help streamline the process of identifying cases, tracking variants, and detecting co-infecting viruses. At present, separate assays and complex workflows are involved in each of these three diagnostic procedures, with analyses typically performed in highly specialized facilities. Researchers have now combined all three kinds of tests into a single procedure that should allow for point-of-care tracking of COVID-19 and the many emerging variants of SARS-CoV-2.
The test involves a portable, briefcase-sized mini-laboratory that avoids the slow and expensive techniques that are standard for COVID-19 screening and monitoring. The test takes advantage of a genetic method (called recombinase polymerase amplification) and a portable sequencer to quickly detect the presence of viral sequences and provide readouts in up to 96 patient samples at a time.
The test was designed to decode five segments of the SARS-CoV-2 genome, each chosen to help guide variant tracking. The researchers also incorporated assays for three common respiratory viruses that can cause symptoms similar to COVID-19.
The team validated the technique — called NIRVANA — using nose and throat swabs from people suspected of having SARS-CoV-2 infections. They also tested wastewater samples collected from municipal sewage to show how the method could allow for population-level surveillance of SARS-CoV-2 and other viruses.
One limitation of the test is that it can only detect SARS-CoV-2 mutations in selected genomic regions and as new variants of concern keep cropping up around the world, those regions might need to be updated to reflect the evolving nature of the virus.