US authority warns: self-tests recognize Omikron worse than other variants

Created: 12/29/2021, 10:58 AM

By: Marc Dimitriu

Corona self-tests apparently do not recognize the Omikron variant so well.

© Wassilis Aswestopoulos via www.imago-images.de

Corona self-tests are ubiquitous.

But new findings on the Omikron variant are causing concern.

The antigen tests apparently recognize them less well than other variants.

Washington, DC - Corona self-tests are an important part of fighting corona.

Since the so-called antigen tests have become available in many supermarkets, they have found many buyers.

Family celebrations at Christmas, birthday parties or just meeting friends.

To be sure, many resort to the self-test beforehand.

While they are not as accurate as the PCR tests, they work well too.

FDA: Omikron does not recognize self-tests as well as other corona variants

But problems could arise with the emerging omicron variant. According to the US health authorities, the self-tests probably do not detect a corona infection with Omikron as well as previous variants. "Initial data indicate that antigen tests may detect the Omicron variant, but may have a lower sensitivity," said the US Food and Drug Administration (FDA) on Tuesday, December 28th. Sensitivity is a measure of how likely it is that a test will show a positive result if an infection is present.

The new data are based on initial research with live viruses from real patients.

The FDA had previously examined the tests with killed viruses and could not find any differences between different corona variants.

According to the FDA, the new data better reflect reality - but the studies are not yet complete.

FDA recommends self-testing anyway - but PCR is more reliable

However, the FDA stated that the use of antigen testing is still recommended - but people should follow official directions.

In some of the so-called quick tests, for example, the user is instructed to perform two tests spaced apart by a certain period of time in order to confirm a negative finding.

If a person tested negative with a rapid test but is likely to have Covid due to symptoms or their proximity to infected people, they are still advised to take a PCR test - which is still the "gold standard" for detecting coronavirus. Infections is.

Corona: self-test or PCR?

This is how the corona tests work

The difference between PCR tests and antigen tests is that the latter react to protein fragments (proteins) from the envelope of the virus.

However, this is mutated in numerous places in the Omikron variant.

PCR tests, on the other hand, prove the genetic material of the virus.

They are more accurate because they can make millions of copies of the virus's RNA so that even the smallest amounts can be detected.

The advantage of antigen tests, however, is that they can be used at home, show a result in minutes, and are inexpensive, whereas PCR tests take hours and require samples to be examined in a laboratory.

In addition to vaccination, both types of test are an indispensable part of a comprehensive strategy to contain the pandemic.

(md with AFP)