A new portable virus screening test can diagnose COVID-19 in minutes and track variants

Clinicians using the new virus screening test can not only diagnose COVID-19 in minutes on a portable pocket-sized machine, but also simultaneously test for other viruses such as influenza that can be mistaken for coronavirus. can also do. At the same time, they can sequence the virus and provide valuable information on the mutation and spread of COVID-19. A new test called NIRVANA was described online today by a team of journal scientists from multiple institutions. When.

This is a virus detection and monitoring method that does not require expensive infrastructure like other approaches. With one portable test, you can achieve the same thing that others are using two or three different tests on different machines. “

Juan Carlos Izpisua Belmonte, co-author and professor at the Salk Institute for Biological Expressions

Worldwide, more than 100 million people are infected with SARS-CoV-2, the virus that causes COVID-19. So far, an astonishing 500,000 Americans have died in COVID-19. Testing the population is the key to stopping the spread of the virus. In addition, it is important to track the spread of new SARS-CoV-2 mutants, some of which may respond differently to treatment or vaccine.

Today, the standard approach for determining whether a nasal swab is positive for COVID-19 is to perform a polymerase chain reaction (PCR) test to detect genetic material from the SARS-CoV-2 virus. is. However, if the sample is negative, the patient and clinician may be causing coronavirus-like symptoms unless they perform separate PCR tests with different swab samples for other viruses. Does not get information. Also, if the sample is SARS-CoV-2 positive, it will not learn the COVID-19 variant that the patient is infected with unless another series of tests is performed. They require large and expensive next-generation gene sequencing machines.

Last summer, Mo Li, an assistant professor of biological sciences at King Abdullah University of Science and Technology in Saudi Arabia, was wondering how his expertise in genetic engineering and nanopore sequencing could be used to combat the COVID-19 pandemic. .. Lee, who previously spent six years as a postdoctoral fellow at the Izpisua Belmonte lab, said that a combination of a gene detection approach called isothermal recombinase polymerase amplification (RPA) and real-time nanopore sequencing would be more useful, faster, and cheaper. I was wondering. It is more portable than the current COVID-19 test approach. He worked with Izpisua Belmonte to investigate.

Unlike PCR, which circulates cold and hot to separate and copy DNA strands, RPA uses proteins rather than temperature changes to achieve the same in just 20 minutes. This technique allows researchers to copy longer DNA and examine multiple genes at the same time.

“I quickly realized that I could use this technology to detect not only SARS-CoV-2, but other viruses at the same time,” says Li.

In a new treatise, Li and Izpisua Belmonte describe a small portable device that can simultaneously screen 96 samples using the RPA assay. They call the method NIRVANA for “nanopore sequencing of isothermal rapid virus amplification for near real-time analysis”.

Scientists have designed NIRVANA to simultaneously test samples of COVID-19, influenza A, human adenovirus, and non-SARS-CoV-2 human coronavirus. In just 15 minutes, researchers report, the device begins to report positive and negative results. And within 3 hours, the device confirms the results for all 96 samples. It contains a sequence of five regions of SARS-CoV-2. These regions tend to accumulate mutations, leading to new variants such as the B.1.1.7 variant. England.

Li and Izpisua Belmonte were found in 10 samples known to be SARS-CoV-2 positive, 60 samples with unknown SARS-CoV-2 status, and urban sewage samples containing the SARS-COV-2 virus. I tested NIRVANA. In all cases, the assay was able to correctly identify which virus was present. Sequencing data also allowed us to narrow down the origin of SARS-CoV-2 in positive samples. For example, differentiation of strains from China and Europe.

“The design of this assay is so flexible that it is not limited to the examples shown so far,” says Li. “We can easily adapt it to tackle another pathogen.

Researchers say the NIRVANA workflow is small in size and highly portable, so it can be used for rapid virus detection in schools, airports and ports. It can also be used to monitor wastewater or streams for the presence of new viruses.

“The pandemic has taught us two important lessons. One is to test widely and quickly, and the second is to know the variants. Our NIRVANA method is not only for current pandemics, but also for future pandemics. We also provide promising solutions to these two challenges, ”Belmonte, chair of Roger Guillemin at Salk. Belmonte needs market analysis to determine the initial cost of commercialization and whether the constant adjustment of tests needed to reliably detect new variants and new viruses of interest is worth it. I add that it will be.