A diagnostic tool for COVID-19 offers an alternative to the current rapid testing. Instead of detecting antibodies or genetic material, the novel tool identifies sugars associated with SARS-CoV-2.
The novel diagnostic tool for COVID-19 was developed by scientists at the University of Warwick, a public research university in England. The tool is a concept in progress to improve existing testing protocols. It specifically targets the sugars linked to the coronavirus in samples, not the antibodies, genetic material, or proteins. Due to the design, the final form may be similar to the pregnancy test, which can be done almost anywhere. They published their findings in the journal ACS Central Science.
The Current Standards in COVID-19 Testing
According to the University of California – Davis, a US public research university, there are two tests available for COVID-19. These tests have been approved to detect the presence of SARS-CoV-2 in people. But the tests target two different things to confirm COVID-19. The gold standard is the viral test or molecule PCR test. It requires samples from the respiratory system. The other test is the antibody test used for quick assessment. It requires blood samples.
Between the two, the PCR test is the most accurate and most invasive screening tool. While the antibody test is the fastest and less accurate in confirming cases. This is because the molecular test finds the coronavirus, not the neutralizing antibodies, which the other test does. A negative antibody test may not mean that the person is truly negative. While a positive antibody test demands confirmation from a molecular test.
Statista, a German portal for statistics, showed the COVID-19 testing capacity of certain countries in May and June 2020. As of May 16, 2020, the number of tests performed by Italy was at 48.71 per 1,000 people, Russia at 45.61, Spain at 41.05 as of May 14, Germany at 37.57 as of May 10, the US at 32.39, the UK at 25.66, South Korea at 14.45, and France at 12.73 as of May 5. The differences in the number of tests performed could be affected by various factors, including the prevalence of outbreaks.
As of June 23, 2020, the UK had the highest per million population COVID-19 test performed at 118,296 per million. It was followed by Spain at 110,426, the US at 87,743, Italy at 82,915, Germany at 60,036, Sweden at 38,192, France at 21,214, Brazil at 11,814, and India at 5,173 per million. These figures only covered select countries by Worldometers.
In the US, several states were found with more than 10% of COVID-19 positive case rate as of June 30, 2020. Arizona was at 24.4%, followed by Florida at 15.6%, Alabama at 15.2%, Nevada at 15.1%, Texas 14.1%, Mississippi at 14.1%, South Carolina at 13.7%, Georgia at 11.7%, and Utah at 10.9%. The World Health Organization recommends a 5% positive case rate for two weeks to ease movement restrictions.
COVID-19 Test That Detects the Coronavirus' Sugars
Certain tests for COVID-19 identify the presence of antibodies, proteins, and genetic material. But these targets either lower the accuracy of a test or raise the requirement for specialized lab instruments. So, a group of scientists developed a novel diagnostic tool that screens for sugars. The tool detects sugars called glycans to identify SARS-CoV-2 in samples. It uses the same concept of home pregnancy tests. It also means that the novel tool can be used by almost anyone.
"Our team has now been able to show that this detection technique works with a 'pseudotyped virus'; a safer to handle alternative which mimics SARS-COV-2. This further demonstrated that the diagnostic format can detect actual viruses not just the isolated proteins from its surface," said Matthew Gibson, the corresponding author of the study and professor at the Department of Chemistry at Warwick.
In a collaboration with Iceni Diagnostics and the University of Manchester, the team demonstrated how a diagnostic tool for sugars could work on COVID-19 testing. They applied a pseudotyped virus that mimics SARS-CoV-2 without the risk of infecting anyone. The bogus virus was modified to feature specific traits of the coronavirus. Previous research showed that SARS-CoV-2's spike proteins bind sialic acids, a family of derivatives of neuraminic acid. These are acidic sugars found in various sources, such as food and organisms. Lab tests suggested that the novel tool could detect the sugars of the coronavirus. Glyco-nanomaterials were utilized to identify certain parts of SARS-CoV-2, which allowed the targeted screening. While the tool could not replace molecular tests, it would be a significant addition to rapid testing.
First, screening for sugars may likely be more accurate than screening for antibodies. Some people take time to develop neutralizing antibodies, which rapid testing can miss. Second, the test is simple enough to understand even without training. There is no need for specialization among healthcare professionals to perform the test. Third, no dedicated infrastructure is needed to support the test. Molecular COVID-19 tests require infrastructure to safely test samples. The novel sugar test can be done without a lab. And finally, it is cheaper than the gold standard. Without the need for labs, the cost of a single kit is substantially reduced.
Right now, the new diagnostic sugar-based tool for COVID-19 is still in development. Scientists are optimizing the entire testing process. They have to ensure the safety and efficiency in screening samples. As such, they are now making adjustments to apply their method in real patients and other existing diagnostic tools. One interesting subject is how will the sugar-based test fare against rapid antibody tests.
The team is seeking investment or philanthropic partners to further develop the technology. They need it to push the novel tool to initial clinical evaluation. If the tool works better than antibody tests, it can be deployed in areas where molecular labs are far. It can be used in areas where community transmission is high. And if new outbreaks start, the same novel tool may help find even asymptomatic carriers.