Omicron subtype BA.2: how dangerous is the coronavirus variant?

Created: 03/27/2022, 15:10

By: Martina Lippl

Omicron BA.2: The sub-variant is spreading rapidly and is displacing BA1 all over the world.

© Leonello Calvetti/imago

The omicron subtype BA.2 prevails in Germany.

It is significantly more contagious than the previously dominant variant BA.1.

The most important questions and answers.

Munich – Viruses mutate, that's in their nature and most people are probably familiar with it by now.

The Sars-CoV-2 coronavirus is no exception.

However, no one had Omikron on their radar.

The coronavirus variant first emerged in late November and quickly spread around the world.

Now things are bubbling up again: the

is even faster.

That could prolong the current fifth corona wave.

Omicron subtype BA.2: is the subvariant more dangerous?

The omicron subtype BA.2 has already displaced the subtype BA.1 in many countries - Denmark, Great Britain and South Africa.

In Germany, the proportion has risen from almost 25 percent to 38 percent, as reported by the Robert Koch Institute (RKI) in its current weekly report on Thursday.

However, the values ​​refer to the previous week, in this case to calendar week 8. The proportion will probably be significantly higher now.

Researchers are trying to understand why the omicron subvariant BA.2 is now displacing variant BA.1 so quickly.

The steady increase in the prevalence of BA.2 in several countries suggests that it has a growth advantage over other circulating variants, says Mads Albertsen, a bioinformatician at Aalborg University in Denmark in the journal

.

"BA.2 obviously has high growth potential," says the Bremen epidemiologist Hajo Zeeb, as reported by the dpa news agency.

This could be due to better transmissibility and/or even stronger immune evasion, i.e. the ability to evade antibodies from vaccinated and recovered people.

Corona: how many omicron subtypes are there?

Corona: Omikron BA.2 "much more contagious"

According to the RKI, initial studies from Denmark and Great Britain indicate that subvariant BA.2 is significantly more transferrable than omicron variant BA.1.

The difference in portability appears to be much smaller than, for example, the difference between BA.1 and Delta.

For the difference between BA.1 and BA.2, the Charité virologist Christian Drosten tried a car comparison: Both have almost the same width tires, but in the case of BA.2 the engine has "a few more horsepower". 

Corona: Severe disease progression in Omikron BA.2?

Even if BA.2 seems more infectious - about 1.4 times - there are no signs of severe disease progression.

However, the observations come from countries with many vaccinated and recovered such as South Africa, Great Britain and Denmark.

Virologist Drosten recently said that he was hoping for findings from Hong Kong, where many older people were very hesitant about the vaccination and where Omicron shows a high burden of disease in this group.

In Germany, too, experts are concerned about the relatively large group of older people without vaccination protection.

The WHO also points to preliminary laboratory data from Japan: In hamsters without immune protection, BA.2 caused serious diseases compared to BA.1.

Corona: What does the omicron subvariant mean for Germany?

The rapid spread of BA.2 could put another critical strain on the healthcare system.

Precisely because the Corona rules will be relaxed in Germany from March 4th.

"Due to the easier transferability of subline BA.2, a significantly slower decrease or renewed increase in the number of cases cannot be ruled out," writes the RKI.

An important factor for the further course is how much contacts increase as part of the planned easing.

After a long decline in the incidence, the RKI reported a slight increase on Friday.

Is this the first indication of a trend reversal?

Experts have feared for weeks that the spread of BA.2 could prolong the omicron wave and slow the decline in case numbers.

Omikron: What is the difference between BA.2 and BA.1?

The subvariants BA.2 and BA.1 differ in their genetic sequence – at a total of 27 locations in the genome.

The omicron subtype BA.2 shows numerous mutations - especially in the spike protein.

These mutations appear to make BA.2 more easily transmissible and therefore more contagious.

Both omicron variants trick the immune system and avoid antibodies.

Despite vaccination, people get sick with Covid.

In the case of those who have been boosted – i.e. those who have been vaccinated three times – the course is usually mild.

Does Omicron BA.1 infection protect against BA.2?

According to Danish findings, it is possible to be infected with BA.1 and BA.2 one after the other.

However, it is assumed that this occurs relatively rarely - and then especially in younger, unvaccinated people.

The WHO states that initial data indicate a strong protection from BA.1 infection against re-infection with BA.2 - at least in the short period for which data are available so far.

Corona vaccinations still protect BA.2 very well against a severe course.

24vita.de* also reports on the omicron subtype.