The relatively mild course of Omikron is currently giving hope that the pandemic will end soon. Many experts are also convinced that the spook could soon come to an end – if there weren’t another report about a new corona sub-variant. Because the number of cases in Denmark has been exploding again for a few days. The reason: A subvariant of omicron called BA.2 dominates the infection process there.
What is known about the subvariant so far:
BA.2 spreads even faster
The original omicron variant (BA.1) itself is considered to be highly contagious. Initial indications now indicate that sub-variant BA.2 is spreading even faster. “We can see from the transmissions in households that BA.2 is more infectious than BA.1,” says Danish virologist Anders Fomsgaard (66) to “Spiegel”. The US epidemiologist Eric Feigl-Ding (38) even believes that BA.2 could spread twice as fast as BA.1. Developments in Denmark worry him. “It took BA.2 just a month to overtake the already super contagious BA.1 guy,” he wrote in a tweet on Sunday.
BA.2 is difficult to detect
Due to a missing spike protein in BA.2, the variant cannot be well identified by previous PCR tests. That’s why BA.2 was also called the “Stealth variant” after its discovery, i.e. “camouflaged variant”. Although the subvariant can be identified with genome sequencing, this is far more complex – BA.2 could often remain undetected.
BA.2 was detected in these countries
So far, BA.2 has been detected in over 40 countries. Including in the USA, China, Australia, Germany and France. In Denmark, BA.2 is already the predominant variant. As the “Aargauer Zeitung” reports, around ten cases of the sub-variant were also registered in this country. However, the Federal Office of Public Health (BAG) does not yet show these separately on their Corona dashboard.
This is how the original and BA.2 differ
One of the first researchers to look at subvariant BA.2 is the Austrian geneticist Ulrich Elling. According to him, the difference between BA.1 and BA.2 is quite large – there are 17 mutations between the two types. The difference is therefore greater than between the wild type from Wuhan and the alpha variant, which was initially also called the British variant. Nevertheless, the World Health Organization (WHO) has not yet differentiated between omicron and the new subvariant.
However, there is only sparse information on subvariant BA.2 so far, much is still unclear and is only just being researched.
What we don’t know about the subvariant yet:
Development of BA.2
No one knows whether BA.2 will catch on in the rest of the world. There is currently a lack of data for this. But one thing is clear: In countries where BA.2 already accounts for a high proportion of infections, there have been significant increases in the number of infections. How the sub-variant could affect Switzerland can only be speculated about. However, a development like that in Denmark would be conceivable. Because the number of cases there developed almost identically to those in Switzerland – albeit with a lead of around three weeks.
severity of the disease
In the case of infection with the previous Omikron variant, the cases were mostly mild – in this country there was no significant increase in hospitalizations due to Omikron. It is still unclear whether this would also be the case with BA.2. However, initial evaluations from Denmark show that there are still no differences in hospitalizations between BA.1 and BA.2.
Infectiologist Huldrych Günthard: «We have practically no omicron cases on the IPS»(01:42)
Vaccination protection against BA.2
How well the previous vaccinations protect against the sub-variant is currently being examined. It is also unclear whether people who have already been infected with BA.1 are now protected from the subvariant. In any case, the first data from Denmark present the researchers with another puzzle – above all people who have been boosted have become infected with BA.2.
The origin of BA.2
Although Denmark is making headlines with its many BA.2 cases, it is still unclear where the subvariant originated. According to the television channel «France24», BA.2 was detected in South Africa and India at the end of December 2021. It is not yet known whether the sub-variant originated in one of these countries.