The omicron variant of the coronavirus has not yet been adequately researched. An institute is now commenting on initial doubts about the reliability of rapid tests.
Update from Thursday, December 30th, 2021, 2 p.m .: The Paul Ehrlich Institute, which is responsible for vaccines and biomedical drugs in Germany, points to previous study results, according to which “the vast majority of the antigen tests offered in Germany and rated positively have an omicron infection can prove “. The institute reported this in response to a notification from the US health authority FDA, which had warned that rapid antigen tests may less reliably detect the new corona variant than previous virus variants (see first report).
As a justification, the Paul Ehrlich Institute stated that a large number of the antigen tests available in Germany detect the nucleo-protein of the corona virus, which is much more conserved in samples. The mutations of the omicron variant, however, mainly affect the spike protein. In addition, “two of the total of four mutations in the omicron N protein also occurred in the previously known SARS-CoV-2 variants” and had “no influence on the reliability of the antigen detection tests”.
Omikron: How reliable are rapid antigen tests?
To this end, the Paul Ehrlich Institute refers to a review of 245 types of antigen tests that have been randomly examined by a test laboratory for a year. By December 14, 2021, 199 of the examined antigen tests had passed the test and 46 products were classified as unsatisfactory. According to this, 80 percent of the tests examined had “the sensitivity required in the comparison test.”
In general, the researchers point out that the antigen tests “were not developed to reliably diagnose SARS-CoV-2 infection”, but “to quickly identify people with a very high viral load, the associated potential infectiousness and the risk of transmission for contact persons and easy to identify ”. According to the Paul Ehrlich Institute, further investigations, especially in the form of comparative studies with samples from Omikron-infected people, are required for a final, qualitative and quantitative statement.
Detecting the Omikron variant: According to the US FDA, rapid tests may be inaccurate
First report from Wednesday, December 29th, 2021, 10:00 a.m .: Washington DC – As the US health authority reports, rapid antigen tests probably do not detect a corona infection with the omicron variant as well as previous variants. “First data indicate that antigen tests recognize the Omikron variant, but may have a lower sensitivity,” said the FDA on Tuesday (12/28/2021). Sensitivity is a measure of the probability that a test will show a positive result for an existing corona infection.
The current data are based on initial research results 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 have not yet been completed.
Corona variant Omikron: Follow the official instructions for rapid antigen tests
The FDA also stated that the use of antigen testing is still recommended, but people should follow official directions. For example, with some of the so-called rapid tests, users are instructed to perform two tests at a certain interval in order to confirm a negative result.
If a person tested negative with a rapid test but is likely to have Covid-19 due to symptoms or their proximity to corona infected people, it is still recommended that they take a PCR test – the “gold standard” for detecting corona Infections.
Corona variant Omikron: Tests essential for pandemic containment
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. In contrast, PCR tests reveal 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.
However, antigen tests can also be used at home and show a result within minutes. They are inexpensive, while PCR tests take hours and require samples to be examined in a laboratory. As before, both types of test, in addition to the corona vaccination, are an indispensable part of a comprehensive strategy to contain the corona pandemic. (ktho / ska with AFP)
