Los Angeles, April 1
Scientists have developed a new portable, pocket-sized test that can not only diagnose Covid-19 in minutes but also sequence the coronavirus to track the spread of mutations and variants.
The test, dubbed NIRVANA, can simultaneously test for other viruses such as influenza that might be mistaken for the coronavirus, the researchers said.
“This is a virus detection and surveillance method that doesn’t require an expensive infrastructure like other approaches,” said Juan Carlos Izpisua Belmonte, a professor at the Salk Institute for Biological Studies in the US.
“We can accomplish with one portable test the same thing that others are using two or three different tests, with different machines, to do,” Belmonte said.
The researchers noted that testing the population is key to stopping the spread of the virus.
Also, tracking the spread of new SARS-CoV-2 variants — some of which could respond differently to treatments or vaccines — is critical, they said.
The current standard approach to determine whether a nasal swab is positive for Covid-19 is to run a polymerase chain reaction (PCR) test to detect genetic material from the SARS-CoV-2 virus.
However, if the sample is negative, patients and clinicians don’t get any information on what might be causing the coronavirus-like symptoms — unless they run separate PCR tests, using different swab samples, for other viruses.
Even if the sample is positive for SARS-CoV-2, they don’t learn which Covid-19 variant a patient is infected with unless another set of tests is run, which require a large and expensive next-generation gene-sequencing machine.
Mo Li, an assistant professor at King Abdullah University of Science and Technology in Saudi Arabia, wondered whether a gene-detection approach called isothermal recombinase polymerase amplification (RPA) coupled with real-time nanopore sequencing might be more useful than the current COVID-19 testing approach.
Unlike PCR, which cycles through lower and higher temperatures to separate DNA strands and copy them, RPA uses proteins — rather than temperature changes — to accomplish the same thing in only 20 minutes.
The technology lets researchers copy longer stretches of DNA, and probe for multiple genes at the same time.
“We quickly realised that we could use this technique to not only detect SARS-CoV-2, but other viruses at the same time,” said Li.
The study, published in the journal Med, describes a small, portable device that can screen 96 samples at the same time using the RPA assay. PTI