Covid, the turning point: the quick test arrives that identifies the variants in a few hours. How it works and what changes

The CoVarScan test is able to detect coronavirus positivity but also to identify the Covid variant: how it works and what changes

By: VirgilioNotizie | Posted on:





New turning point in the fight against Covid-19: researchers fromUT Southwestern Medical Center in Dallas they announced that they have created a quick test, CoVarScan, able to detect coronavirus positivity but also to identify the variant.

Until now, scientists have had to resort to whole genome sequencing to identify the variant, a time-consuming and costly operation that takes several days. Now, however, the situation changes.

What changes with the CoVarScan test

As reported by the ‘Corriere della Sera’, Jeffrey SoRelleprofessor of pathology and senior author of the study published in the journal Clinical Chemistry, announced that using the CoVarScan test “we can very quickly determine which variants are present in the community and if a new variant is emerging.”

According to the researchers, CoVarScan could prove particularly useful for monitoring the spread of variants and for making faster clinical decisions, particularly regarding the choice of monoclonals (which work differently depending on the strain).

Pierangelo Clerici, president of the Italian Clinical Microbiologists Association, commented: “Knowing the diffusion of variants quickly is useful if the numbers are important, like now; less if the numbers were to go down. We do not know what the cost of the device will be, so at the moment we cannot assess whether the cost-benefits will be real ”.

Clerici himself added: “Today the same antivirals are used to combat Covid-19 regardless of the variants. Monoclonals are an exception. However, if in the future ad hoc therapies are available according to the variants, the test could be very useful “.

Covid, the turning point: the quick test arrives that identifies the variants in a few hours. How it works and what changesPhoto source: ANSA

A new test for Covid is coming that identifies variants in a few hours.

How the CoVarScan test works

The CoVarScan test focuses on 8 regions of the Sars-CoV-2 genome that differ between viral variants. The test detects small mutations (in which the sequence of RNA blocks varies) and measures the length of some genetic regions that tend to grow or contract with the evolution of the virus. The method is based on polymerase chain reaction (PCR), a common technique in most pathology laboratories, to copy and measure RNA at these 8 sites of interest.

The effectiveness of CoVarScan has been tested on over 4,000 Covid-19 positive nasal swab samples, collected between April 2021 and February 2022.

Compared to whole genome sequencing, CoVarScan showed a sensitivity of 96% and a specificity of 99%. The test managed to identify the Delta, Mu, Lambda and Omicron variants, including the BA.2 version.

The limitations of the CoVarScan test

One of the possible limitations of CoVarScan is related to the fact that, as the months go by, they continue to emerge new variants of coronavirus and this may require a continuous update of the test. SoRelle replied: “The CoVarScan hasn’t needed any adjustments in over a year and continues to perform very well. In the future, if we need to fix it, we could easily add another 20 or 30 hotspots to the test. “

Another limitation concerns the sensitivity of the test. Pierangelo Clerici explained: “In 95% of the cases tested, the intercepted viral load was high, with an infectious value, but in a non-negligible percentage the test also identified swabs with a very low viral load, considered non-infectious, as positive. Even individuals who cannot infect them would be positive “.



Covid test

Photo source: ANSA



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Covid, the turning point: the quick test arrives that identifies the variants in a few hours. How it works and what changes


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