Researchers used CRISPR-based assays to develop new clinical laboratory point-of-care blood test which boasts accuracy, affordability, and accessibility
According to UPI, the test can “distinguish between influenza A and influenza B—the two main types of seasonal flu—as well as identifying more virulent strains like H1N1 and H3N2.”
Many research teams are working to develop paper-based diagnostic screening tests because of their lower cost to produce and usefulness in remote locations. Should this near-patient point-of-care test become clinically viable, it could mean shorter times to answer, enabling speedier diagnoses and earlier start of treatment.
It also means patient specimens do not have to be transported to a clinical laboratory for testing. And reduced cost per test makes it possible to test more people. This serves the public health aspect of monitoring outbreaks of influenza and other diseases and gives hope for improved treatment outcomes.
“Being able to tease apart what strain or subtype of influenza is infecting a patient has repercussions both for treating them and public health interventions, said Jon Arizti Sanz, PhD, co-lead study author and postdoctoral researcher at the Broad Institute of Harvard and MIT, in a Broad Institute news release.
“Ultimately, we hope these tests will be as simple as rapid antigen tests, and they’ll still have the specificity and performance of a nucleic acid test that would normally be done in a laboratory setting,” Cameron A. Myhrvold, PhD (above), Assistant Professor of Molecular Biology at Princeton University in New Jersey, told CIDRAP. Influenza tests that can be performed at the point of care and in remote locations may reduce the number of screening tests performed by clinical laboratories. (Photo copyright: Michael James Butts/Hertz Foundation.)
Her team developed their tests using Streamlined Highlighting of Infections to Navigate Epidemics (SHINE), “a clustered regularly interspaced short palindromic repeats (CRISPR)-based RNA detection platform,” the researchers wrote in their Journal of Molecular Diagnostics paper.
“SHINE has a runtime of 90 minutes, can be used at room temperature and only requires an inexpensive heat block to heat the reaction. The SHINE technology has previously been used to identify SARS-CoV-2 and later to distinguish between the Delta and Omicron variants,” Bioanalysis Zone reported.
“The test uses genetically engineered enzymes to identify specific sequences of viral RNA in samples,” the researchers told UPI. Originally designed to detect COVID-19, the team adapted the technology to detect influenza in 2022 “with the aim of creating a screening tool that could be used in the field or in clinics rather than hospitals or high-tech diagnostic labs,” they said.
Influenza A and B as well as H1N1 and H3N2 subtypes were the targets of the four SHINE assays. “When tested on clinical samples, these optimized assays achieved 100% concordance with quantitative RT-PCR. Duplex Cas12a/Cas13a SHINE assays were also developed to detect two targets simultaneously,” the researchers wrote in their paper.
The team used “20 nasal swabs from people with flu-like symptoms during the 2020-2021 flu season, nasal fluid from healthy people as the control, and 2016-2021 influenza sequences downloaded from the National Center for Biotechnology Information Influenza (NICB) database. They compared the results with those from quantitative reverse transcription-polymerase chain reaction (RT-PCR) tests,” CIDRAP reported.
The original 2020 test (shown above) takes 90 minutes to develop at room temperature. The test developers aim to drop this down to 15 minutes. In comparison, typical polymerase chain reaction (PCR) testing requires medical laboratories to have specialized equipment, trained staff, and prolonged processing times, the Broad Institute news release notes. (Photo copyright: Broad Institute.)
Implications of the New Tests
The ease of the new tests is an important development since approximately only 1% of individuals who come down with the flu see doctors for testing, according to the news release. And researchers had this in mind, looking at speed, accuracy, and affordability as a means to “improve outbreak response and infection care around the world,” UPI reported.
There are great benefits to strain differentiation that be achieved with the new test. Doctors are hopeful the test will help dial in the best treatment plans for patients since some strains are resistant to the antiviral medication oseltamivir (Tamiflu), UPI noted. This is significant since Tamiflu “is a common antiviral,” said Sanz in the Broad Institute news release.
“These assays have the potential to expand influenza detection outside of clinical laboratories for enhanced influenza diagnosis and surveillance,” the Journal of Molecular Diagnostics paper noted. This allows for more strategic treatment planning.
“Using a paper strip readout instead of expensive fluorescence machinery is a big advancement, not only in terms of clinical care but also for epidemiological surveillance purposes,” said Ben Zhang, an MD candidate in the Health Sciences and Technology at Harvard and co-first author of the study, in the Broad Institute news release.
Future Plans for Tests
“With further development, the test strip could be reprogrammed to distinguish between SARS-CoV-2 and flu and recognize swine flu and avian flu, including the H5N1 subtype currently causing an outbreak in US dairy cattle,” the study authors told CIDRAP.
The team is also looking at ways to help prevent H5N1 from crossing into human contamination, Sanz told UPI.
The new Princeton/MIT/Harvard tests echo the trend to bring in affordability and ease-of-use with accurate results as an end goal. Faster results mean the best treatments for each person can start sooner and may render the transport of specimens to a clinical laboratory as a second step unnecessary.
As research teams work to develop paper-based viral tests for their plethora of benefits, clinical laboratories will want to pay close attention to this development as it can have a big implication on assisting with future outbreaks.
Additional research is needed before these tests are going to be commonplace in homes worldwide, but this first step brings inspiration and hope of what’s to come.
Many of the mutations were found at sites on the spike protein where antibodies bind, which may explain why the Omicron variant is more infectious than previous variants
Scientists at the University of Missouri (UM) now have a better understanding of why the SARS-CoV-2 Omicron variant is more infectious than previous variants and that knowledge may lead to improved antivirals and clinical laboratory tests for COVID-19.
As the Omicron variant of the coronavirus spread across the globe, scientists noted it appeared to be more contagious than previous variants and seemed resistant to the existing vaccines. As time went by it also appeared to increase risk for reinfection.
The UM researchers wanted to know why. They began by examining the Omicron variant’s mutation distribution, its evolutionary relationship to previous COVID-19 variants, and the structural impact of its mutations on antibody binding. They then analyzed protein sequences of Omicron variant samples collected from around the world.
“We know that viruses evolve over time and acquire mutations, so when we first heard of the new Omicron variant, we wanted to identify the mutations specific to this variant,” said Kamlendra Singh, PhD, Associate Research Professor, Department of Veterinary Pathobiology at UM’s College of Veterinary Medicine (CVM), in a UM press release.
Kamlendra Singh, PhD (above), an associate research professor in the Department of Veterinary Pathobiology at UM’s College of Veterinary Medicine, led the team that identified 46 mutations of the SARS-CoV-2 Omicron variant. “I went to India last April and I got infected by the Delta variant. So, it then became personal to me,” he told NBC affiliate KOMU. The UM team hopes their findings lead to improvements in existing COVID-19 antivirals and clinical laboratory tests. (Photo copyright: University of Missouri.)
In their paper, the UM team wrote, “Here we present the analyses of mutation distribution, the evolutionary relationship of Omicron with previous variants, and probable structural impact of mutations on antibody binding. … The structural analyses showed that several mutations are localized to the region of the S protein [coronavirus spike protein] that is the major target of antibodies, suggesting that the mutations in the Omicron variant may affect the binding affinities of antibodies to the S protein.”
There are a total of 46 highly prevalent mutations throughout the Omicron variant.
Twenty-three of the 46 mutations belong to the S protein (more than any previous variant).
Twenty-three of 46 is a markedly higher number of S protein mutations than reported for any SARS-CoV-2 variant.
A significant number of Omicron mutations are at the antibody binding surface of the S protein.
“Mutation is change in the genome that results in a different type of protein,” Singh told NBC affiliate KOMU. “Once you have different kinds of protein after the virus and the virus attacks the cell, our antibodies do not recognize that, because it has already been mutated.”
Omicron Mutations Interfere with Antibody Binding
Of the 46 Omicron variant mutations discovered by the UM researchers, some were found in areas of the coronavirus’ spike protein where antibodies normally bind to prevent infection or reinfection.
“The purpose of antibodies is to recognize the virus and stop the binding, which prevents infection,” Singh explained. “However, we found many of the mutations in the Omicron variant are located right where the antibodies are supposed to bind, so we are showing how the virus continues to evolve in a way that it can potentially escape or evade the existing antibodies, and therefore continue to infect so many people.”
These findings explain how the Omicron variant bypasses pre-existing antibodies in a person’s blood to cause initial infection as well as reinfection.
The UM team hopes their research will help other scientists better understand how the SARS-CoV-2 coronavirus has evolved and lead to future clinical laboratory antiviral treatments.
“The first step toward solving a problem is getting a better understanding of the specific problem in the first place,” Singh said. “It feels good to be contributing to research that is helping out with the pandemic situation, which has obviously been affecting people all over the world.”
Singh and his team have developed a supplement called CoroQuil-Zn designed to reduce a patient’s viral load after being infected with the SARS-CoV-2 coronavirus. The drug is currently being used in parts of India and is awaiting approval from the US Food and Drug Administration (FDA).
New discoveries about SARS-CoV-2 and its variants continue to further understanding of the coronavirus. Research such as that performed at the University of Missouri may lead to new clinical laboratory tests, more effective treatments, and improved vaccines that could save thousands of lives worldwide.
Given the large number of mutations found in the SARS-CoV-2 Omicron variant, experts in South Africa speculate it likely evolved in someone with a compromised immune system
As the SARS-CoV-2 Omicron variant spreads around the United States and the rest of the world, infectious disease experts in South Africa have been investigating how the variant developed so many mutations. One hypothesis is that it evolved over time in the body of an immunosuppressed person, such as a cancer patient, transplant recipient, or someone with uncontrolled human immunodeficiency virus infection (HIV).
One interesting facet in the story of how the Omicron variant was being tracked as it emerged in South Africa is the role of several medical laboratories in the country that reported genetic sequences associated with Omicron. This allowed researchers in South Africa to more quickly identify the growing range of mutations found in different samples of the Omicron virus.
“Normally your immune system would kick a virus out fairly quickly, if fully functional,” Linda-Gail Bekker, PhD, of the Desmond Tutu Health Foundation (formerly the Desmond Tutu HIV Foundation) in Cape Town, South Africa, told the BBC.
“In someone where immunity is suppressed, then we see virus persisting,” she added. “And it doesn’t just sit around, it replicates. And as it replicates it undergoes potential mutations. And in somebody where immunity is suppressed that virus may be able to continue for many months—mutating as it goes.”
Multiple factors can suppress the immune system, experts say, but some are pointing to HIV as a possible culprit given the likelihood that the variant emerged in sub-Saharan Africa, which has a high population of people living with HIV.
Li “was among the first to detail extensive coronavirus mutations in an immunosuppressed patient,” the LA Times reported. “Under attack by HIV, their T cells are not providing vital support that the immune system’s B cells need to clear an infection.”
Linda-Gail Bekker, PhD (above), of the Desmond Tutu Health Foundation cautions that these findings should not further stigmatize people living with HIV. “It’s important to stress that people who are on anti-retroviral medication—that does restore their immunity,” she told the BBC. (Photo copyright: Test Positive Aware Network.)
Omicron Spreads Rapidly in the US
Genomics surveillance Data from the CDC’s SARS-CoV-2 Tracking system indicates that on Dec. 11, 2021, Omicron accounted for about 7% of the SARS-CoV-2 variants in circulation, the agency reported. But by Dec. 25, the number had jumped to nearly 60%. The data is based on sequencing of SARS-CoV-2 by the agency as well as commercial clinical laboratories and academic laboratories.
Experts have pointed to several likely factors behind the variant’s high rate of transmission. The biggest factor, NPR reported, appears to be the large number of mutations on the spike protein, which the virus uses to attach to human cells. This gives the virus an advantage in evading the body’s immune system, even in people who have been vaccinated.
“The playing field for the virus right now is quite different than it was in the early days,” Joshua Schiffer, MD, of the Fred Hutchinson Cancer Research Center, told NPR. “The majority of variants we’ve seen to date couldn’t survive in this immune environment.”
One study from Norway cited by NPR suggests that Omicron has a shorter incubation period than other variants, which would increase the transmission rate. And researchers have found that it multiplies more rapidly than the Delta variant in the upper respiratory tract, which could facilitate spread when people exhale.
Using Genomics Testing to Determine How Omicron Evolved
But how did the Omicron variant accumulate so many mutations? In a story for The Atlantic, virologist Jesse Bloom, PhD, Professor, Basic Sciences Division, at the Fred Hutchinson Cancer Research Center in Seattle, described Omicron as “a huge jump in evolution,” one that researchers expected to happen “over the span of four or five years.”
Hence the speculation that it evolved in an immunosuppressed person, perhaps due to HIV, though that’s not the only theory. Another is “that the virus infected animals of some kind, acquired lots of mutations as it spread among them, and then jumped back to people—a phenomenon known as reverse zoonosis,” New Scientist reported.
Still, experts are pointing to emergence in someone with a weakened immune system as the most likely cause. One of them, the L.A. Times reported, is Tulio de Oliveira, PhD, Affiliate Professor in the Department of Global Health at the University of Washington. Oliveira leads the Centre for Epidemic Response and Innovation at Stellenbosch University in South Africa, as well as the nation’s Network for Genomic Surveillance.
The Network for Genomic Surveillance, he told The New Yorker, consists of multiple facilities around the country. Team members noticed what he described as a “small uptick” in COVID cases in Gauteng, so on Nov. 19 they decided to step up genomic surveillance in the province. One private clinical laboratory in the network submitted “six genomes of a very mutated virus,” he said. “And, when we looked at the genomes, we got quite worried because they discovered a failure of one of the probes in the PCR testing.”
Looking at national data, the scientists saw that the same failure was on the rise in PCR (Polymerase chain reaction) tests, prompting a request for samples from other medical laboratories. “We got over a hundred samples from over thirty clinics in Gauteng, and we started genotyping, and we analyzed the mutation of the virus,” he told The New Yorker. “We linked all the data with the PCR dropout, the increase of cases in South Africa and of the positivity rate, and then we began to see it might be a very suddenly emerging variant.”
Oliveira’s team first reported the emergence of the new variant to the World Health Organization, on Nov. 24. Two days later, the WHO issued a statement that named the newly classified Omicron variant (B.1.1.529) a “SARS-CoV-2 Variant of Concern.”
Microbiologists and clinical laboratory specialists in the US should keep close watch on Omicron research coming out of South Africa. Fortunately, scientists today have tools to understand the genetic makeup of viruses that did not exist at the time of SARS 2003, Swine flu 2008/9, MERS 2013.
According to the Centers for Disease Control and Prevention (CDC), the 1918 influenza (aka, the Spanish Flu) pandemic took place worldwide between 1918 and 1919. It was caused by the H1N1 virus (A/H1N1), a subtype of the Influenza A virus, and infected approximately 500 million people worldwide (a third of the human population at the time). Fifty million people died. Many were children or otherwise healthy individuals, but people from all age groups perished.
The CDC calls the Spanish Flu the “deadliest pandemic of the 20th century.” Past pandemics have generally concluded after 2.5 to 3.5 years. That’s how long it takes for new viruses to mutate and become endemic diseases, Healthline reported.
The COVID-19 pandemic has been around for about that long. It stands to reason the natural end of the COVID-19 pandemic may be just around the corner. But is it? And is the Omicron variant an indicator that the COVID-19 pandemic is winding down?
“Our analysis suggests that in the US, this combination of characteristics would lead to Omicron replacing Delta as the dominant variant in the next few months and to a higher peak burden of disease than the country saw in the second half of 2021 (but likely below the peak reached in the winter of 2020-21),” the report states.
McKinsey analysts also acknowledged the possible impact of new therapeutics, COVID-19 vaccine booster doses, and public health measures on Omicron spread. “In the short term, an accelerated rollout of booster doses of COVID-19 vaccines is likely to be one of the best protections against an Omicron-fueled wave of the disease,” the analysts wrote.
Does How the Spanish Flu Came to an End Mirror the COVID-19 Pandemic?
Virologists and infectious disease experts explained that the Spanish Flu virus did what viruses still do: mutate and become less dangerous. Herd immunity also helped end the 1918 pandemic.
“The 1918 influenza virus eventually mutated to the point of not having a high number of deaths—eventually over three years or so. We may very well be witnessing this process with ongoing variants of SARS-CoV-2,” virologist Rodney Rohde, PhD, Director of the Clinical Laboratory Science Program at Texas State University, told Healthline.
Today’s flu strains have “ancestral links” to the 1918 flu, and thus, the SARS-CoV-2 coronavirus will most likely also leave its mark, The Boston Herald reported. “The coronavirus will evolve and hopefully morph into a seasonal illness to which we pay little mind, but it’s still too early to tell,” Todd Ellerin, MD (above,) Director of Infectious Diseases, South Shore Health, South Weymouth, Mass., told The Boston Herald. (Photo copyright: Greg Derr/The Patriot Ledger.)
“If you think about the way viruses behave, biologically, their reason for living is to replicate and spread, and there’s really no advantage for the virus to kill the host,” infectious disease specialist Keith Armitage, MD, Professor of Medicine, Division of Infectious Diseases at Case Western Reserve University, told Healthline. “The hope is, that if the pandemic doesn’t go away, we will get new variants that are highly contagious but don’t produce much of a clinical illness,” he added.
In “2021’s Top 10 Lab Stories Confirm Important Trends,” Dark Daily’s sister publication, The Dark Report (TDR), posed a similar question in its number one story of 2021: “COVID-19: Will it Become Endemic and a Respiratory Virus that Shows Up Every Year like Influenza?”
“The question of whether SARS-CoV-2 is a pandemic that fades, as did SARS in 2003, or becomes endemic and a respiratory virus that shows up every season like influenza and the common cold, is of major concern to clinical lab administrators. That’s because clinical labs and pathology groups must continue to serve physicians and patients with the usual menu of routine, reference, and esoteric testing,” TDR noted.
Clinical Laboratories to Continue COVID Testing
It would be most helpful for medical laboratories and pathology groups to have some idea of when the pandemic will end. Unfortunately, such predictions would not be very useful.
“Since COVID-19 infections have a high number of asymptomatic transmitters, we may not fully understand how societal and environmental pressures—masks, distancing, remote working, etc.—on the virus will allow it to evolve,” Rohde told Healthline.
For now, clinical laboratories will need to continue to remain prepared as COVID-19 cases rise and people seek SARS-COV-2 tests, vaccinations, and treatments. COVID-19 testing is likely to be in demand throughout the coming year. The current surge in demand for COVID-19 tests is putting additional stress on the supply chain.
“We know pandemics end; it’s just a matter of time,” Sara Paton, PhD, Associate Professor of Epidemiology, Wright State University, told the Journal-News. “It could be in 2022, maybe later in the year, but I can’t say for sure. It could be 2023.”
The antibodies target portions of the SARS-CoV-2 spike protein that resist mutation, potentially leading to better treatments and vaccines
One challenge in the battle against COVID-19 is the emergence of SARS-CoV-2 variants, especially the Delta variant, which may be more resistant to neutralizing antibodies compared with the original coronavirus. But now, scientists led by researchers at the Fred Hutchinson Cancer Research Center (Fred Hutch) in Seattle say they have identified antibodies that could be broadly protective against multiple sarbecoviruses, the subgenus that contains SARS-CoV-2 as well as SARS-CoV-1, the virus responsible for the 2002-2004 severe acute respiratory syndrome (SARS) outbreak.
In “SARS-CoV-2 RBD Antibodies That Maximize Breadth and Resistance to Escape,” the researchers described how they compared 12 antibodies obtained from patients infected with either SARS-CoV-2 or SARS-CoV-1. They pointed to one antibody in particular—S2H97—that could lead to development of new vaccines and therapies against current and future variants. It might even protect against sarbecoviruses that have not yet been identified, they wrote.
Unsaid in the news release about these research findings is the fact that these particular antibodies could eventually become useful biomarkers for clinical laboratory tests designed to help physicians determine which patients have these antibodies—and the protection from infection they represent—and which do not.
So far, however, S2H97 has only been tested in hamsters. But results are promising.
“This antibody, which binds to a previously unknown site on the coronavirus spike protein, appears to neutralize all known sarbecoviruses—the genus of coronaviruses that cause respiratory infections in mammals,” said Jay Nix, PhD, an affiliate in Berkeley Lab’s Biosciences Area and Beamline Director of the Molecular Biology Consortium at Berkeley Lab’s Advanced Light Source (ALS), in a Berkeley Lab news release. “And, due to the unique binding site on mutation-resistant part of the virus, it may well be more difficult for a new strain to escape,” he added.
Scientists have long known that the SARS-CoV-2 virus uses the spike protein to attach to human cells. The federal Centers for Disease Control and Prevention (CDC) notes that the variants have mutations in their spike proteins that make some of them more transmissible.
The Delta variant, the CDC notes, was the predominant variant in the US as of August 28, 2021. It “has been shown to have increased transmissibility, potential reduction in neutralization by some monoclonal antibody treatments, and reduction in neutralization by post-vaccination sera,” the agency states.
The key to S2H97, the researchers wrote, is that it targets a portion of the spike protein that is common among sarbecoviruses, and that is likely to be resistant to mutations.
The researchers used a variety of techniques to analyze how the 12 antibodies bind to the virus. They “compiled a list of thousands of mutations in the binding domains of multiple SARS-CoV-2 variants,” Nature reported. “They also catalogued mutations in the binding domain on dozens of SARS-CoV-2-like coronaviruses that belong to a group called the sarbecoviruses. Finally, they assessed how all these mutations affect the 12 antibodies’ ability to stick to the binding domain.”
William Schaffner, MD (above), Professor of Preventive Medicine in the Department of Health Policy as well as Professor of Medicine in the Division of Infectious Diseases at the Vanderbilt University School of Medicine in Nashville, believes that “people who test positive for SARS-CoV-2 and who are at risk of progressing to severe disease—including those who are over the age of 65 years and those who have weakened immune systems—should talk with a doctor about receiving monoclonal antibody treatment,” Medical News Today reported. “[The monoclonal antibody treatment is] designed to prevent the evolution of the infection from a mild infection into a serious one,” he noted. “In other words, you’ve just [contracted the virus], but we can now give you a medication that will help prevent [you] being hospitalized and getting seriously ill.” (Photo copyright: Vanderbilt University.)
Earlier Antibody Treatment Receives an EUA from the FDA
In issuing the EUA for sotrovimab, the FDA cited “an interim analysis from a phase 1/2/3 randomized, double-blind, placebo-controlled clinical trial in 583 non-hospitalized adults with mild-to-moderate COVID-19 symptoms and a positive SARS-CoV-2 test result. Of these patients, 291 received sotrovimab and 292 received a placebo within five days of onset of COVID-19 symptoms.”
Among these patients, 21 in the placebo group were hospitalized or died compared with three who received the therapy, an 85% reduction.
“While preventive measures, including vaccines, can reduce the total number of cases, sotrovimab is an important treatment option for those who become ill with COVID-19 and are at high risk—allowing them to avoid hospitalization or worse,” stated Adrienne E. Shapiro, MD, PhD, of the Fred Hutchinson Cancer Research Center in a GSK news release. Shapiro was an investigator in the clinical trial.
The EUA allows use of sotrovimab in patients who have tested positive for SARS-CoV-2, have mild-to-moderate symptoms, and “who are at high risk for progression to severe COVID-19, including hospitalization or death. This includes, for example, individuals who are 65 years of age and older or individuals who have certain medical conditions.” It is not authorized for patients who are hospitalized or for those who require oxygen therapy.
The therapy was originally known as VIR-7831. The companies say they have developed a similar treatment, VIR-7832, with modifications designed to enhance T cell function against the disease.
The antibody, they wrote, targets a region of the SARS-CoV-1 spike protein that is “highly conserved” among sarbecoviruses. Clinical laboratory testing, they wrote, also indicated that the therapy was likely to be effective against known SARS-CoV-2 variants.
“Our distinctive scientific approach has led to a single monoclonal antibody that, based on an interim analysis, resulted in an 85% reduction in all-cause hospitalizations or death, and has demonstrated, in vitro, that it retains activity against all known variants of concern, including the emerging variant from India,” stated Vir Biotechnology CEO George Scangos, PhD, in the GSK news release. “I believe that sotrovimab is a critical new treatment option in the fight against the current pandemic and potentially for future coronavirus outbreaks, as well.”
Pathologists and clinical laboratory managers working with rapid molecular tests and antibody tests for COVID-19 will want to monitor the development of monoclonal antibody treatments, as well as further research studies that focus on these specific antibodies.
