The world has seen a number of new COVID-19 strains spread the past couple of months. These new strains are created when the virus mutates. Given that they’re mutations of the original virus, there are worries it could cause problems in detecting the virus in testing.
Can the new strains still be detected by COVID-19 tests like PCR tests?
So far, yes. There’s no evidence the latest strains have impacted testing as of yet. However, there is a possibility later mutations could hamper testing and force it to change.
WHY WE ARE VERIFYING
A number of viewers have asked about the new strains, particularly about how they’re detected and if current COVID-19 tests can still detect them.
WHAT WE FOUND
An early January press release from LabCorp, a company that provides PCR tests, stated “we have not seen any impact” to testing sensitivity from COVID-19 mutations to that point.
In a World Health Organization news release tracking COVID-19 variants, the WHO did not state any of the new variants had an impact on the effectiveness of diagnostic testing. While they specified some variants specifically had no impact on the effectiveness to this point, they stated they were still researching some and others were not anticipated to have a significant impact.
That expectation was echoed by the CDC. While they identified the potential to evade detection by specific diagnostic tests as a possible consequence of the evolving COVID-19 variants, they said it’s unlikely to be a problem. “Most commercial PCR tests have multiple targets to detect the virus, such that even if a mutation impacts one of the targets, the other PCR targets will still work.”
Still, each of these statements has included language to indicate that they haven’t seen any impact on testing effectiveness so far. That’s because the potential of a future mutation impacting testing accuracy is possible.
The FDA sent a letter to health care providers in early January warning about such a possibility. The letter stated that genetic variants may lead to false negatives in molecular tests and that tests that detect multiple genetic targets are less susceptible to these effects than tests that detect a single genetic target.
Dr. Stuart Ray, vice chair of medicine for data integrity and analytics professor of medicine at Johns Hopkins Medicine, explained that there aren’t routine clinical laboratory tests for identifying one strain of COVID-19 over another. He said new strains are detected through sequencing the genome of the virus and comparing it to previously sequenced genomes of the virus. “The methods for sequencing all variants of SARS-CoV-2 are also basically the same; however, sequencing of the virus (to determine what variant it is) remains relatively uncommon,” he explained.
A test not being able to differentiate between one COVID-19 variant and another is fine at the moment as long as the test can still accurately detect the virus’ presence because, right now, the clinical treatment for COVID-19 is the same regardless of what variant of the virus a person has, he said.
If the pandemic is kept under control, the potential of it mutating in a way that diagnostic testing can’t detect or even in a way that’s resistant to the current vaccines is reduced.
“Standard COVID-19 precautions, including masks, distancing, avoiding large gatherings in close spaces, and hand hygiene should remain effective with all of the newer variants. If the newer variants are somewhat more infectious, then we need to be extra careful in sticking to those precautions,” Ray said.
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