Already dominant in Denmark - New omicron subtype causes great concern among experts
Created: 01/26/2022, 05:42
By: Bedrettin Bölükbasi
An employee holds PCR test tubes in his hands in a corona test laboratory of the Limbach Group.
© Uwe Anspach/dpa
New corona variants continue to form.
This time it is a subtype of the highly contagious omicron mutant.
Some experts are already concerned.
Munich – After its discovery, the highly contagious omicron mutation of the coronavirus led to a great deal of excitement and numerous discussions.
Due to its high contagiousness, the developments surrounding the variant were followed with concern and an extreme overload of intensive care units was feared.
However, some studies have given reason to calm down: The mutation usually only leads to a mild course of the disease.
However, this relaxed atmosphere could change quickly now, because a subtype of omicron is currently worrying the experts again - at least in Denmark.
The BA.2 subtype is already dominant there.
But it could also become dangerous for the rest of Europe.
Omicron mutation: New subtype BA.2 predominant in Denmark - Institute warns with press release
BA.2 is not the only subtype of omicron.
There are also BA.1 and BA.3 subtypes.
However, the most relevant so far has been the BA.1 type, which quickly ousted the previous delta variant of the virus and is now dominant worldwide.
So BA.1 is Omicron as the world knows it, you could say.
In the week after Christmas, researchers at Denmark's Statens Serum Institut registered a jump from BA.2 to 20 percent of the sequenced samples.
After noting two weeks later "that the mysterious growth was continuing," researcher Anders Fomsgaard told
, he became aware that the new BA.2 subtype could become dominant in Denmark.
Fomsgaard is Head of the Virus and Microbiological Specialty Diagnostics department at Statens Serum Institut, the Danish central laboratory for infectious diseases and biological threats.
His department did not see any weakening in the dynamics of the BA.2, but rather an increase.
When the BA.2 rate in the country rose to 45 percent in the second week of January, the institute acted.
A press release was published on January 20th, drawing attention to the growth of the BA.2 subtype and the simultaneous decline of BA.1.
Omicron subtype: BA.2 is also spreading to other countries - large differences in spike protein
BA.1's decline is anything but unimportant at this point, as it is taken as a clear indication that another subtype has evolutionary advantages over the other subtype and drives it out.
In the meantime, countries such as Great Britain, Sweden, India and Singapore are also apparently recording an increase in BA.2, as reported by
Fomsgaard also provided descriptions of the new subtype.
You differ by at least ten mutations to the BA.1 subtype.
The differences would affect key sites on the spike protein - the part of the virus it uses to dock and enter human host cells.
In order to provide a better idea, the researcher draws a comparison with the corona variants.
The difference between BA.1 and BA.2 is "roughly the same as in the wild type and the alpha variant," emphasizes the Danish researcher.
Omicron subtype BA.2: The situation in Germany is not yet critical - but international experts are concerned
What is the situation in Germany now?
Although there is less sequencing in this country than in Denmark, the BA.1 subtype was detected much more often than BA.2 in the sequenced samples.
This is shown by the data from the Robert Koch Institute for the first week of January.
Only 38 cases of BA.2 were detected there, while 1,568 cases of the BA.1 subtype were identified.
The situation in Germany is still manageable, but the turning point could come in many countries in the future.
After all, the reports from Denmark are causing concern not only among Danish researchers, but also among international experts.
Based on the data, the US epidemiologist Eric Feigl-Ding, for example, sees two possibilities: either the BA.2 subtype spreads faster or it circumvents immune protection much better than BA.1.
BA.2 could evolve twice as fast as the original version of the omicron mutant, the expert warned, calling for the situation to be taken seriously.
Christina Pagel, a researcher at University College London, echoed her American colleague in arguing that there were “early signs” in England that BA.2 might outperform BA.1.
The British health authority now wants to monitor BA.2 more closely.
Omicron subtype BA.2: Uncertainty about immune resistance and vaccinations - PCR tests probably not reliable
Many experts assume that BA.2 poses a greater risk, but the fact is: too little is known. Further research is needed to better assess the situation. Anders Fomsgaard now wants to take the first steps towards this in his institute. "We are now trying to cultivate the virus in the laboratory to test the immune resistance of BA.2 compared to BA.1," he told
Both the immune resistance and the effect of vaccinations and boosters against the subtype are still unknown.
However, one important problem is known: PCR tests are not always reliable in identifying BA.2, since the subvariant lacks a crucial mutation that is immediately apparent in the PCR test.
Incidentally, this is how the subtype earned the name “stealth variant”.
Genome tests are the better alternative to the PCR test here, but this involves a complex process and thus makes tracking more difficult.