Sunday, May 22

Subgroup of omicrons increases: “Can be even more contagious”

A subgroup of omicrons is kept under special supervision in Norway.

It is called BA.2 and can be even more contagious than the original, states Norwegian FHI.

– Now after New Year, it has increased quite violently, including in Denmark and parts of Sweden, says department head Karoline Bragstad to Dagbladet.

Omikron has in a short time become the dominant variant of the coronavirus, both in Sweden and internationally. The many mutations in the nail protein mean that the virus also infects vaccinated people to a large extent.

But omikron has several subgroups. One of them is called BA.2 and is now kept under special supervision by FHI, Norges equivalent to the Swedish Public Health Agency.

– It has so far had a low prevalence in the world. But now after New Year, it has increased quite violently in Denmark and parts of Sweden, says Karoline Bragstad who is a senior researcher and head of department at FHI to the newspaper Dagbladet.

“Growing trend in Scania”

So far, Norway has registered only a few cases of BA.2. Several of them are imported from Denmark.

– We also see an increasing trend in Skåne, which is closely linked to Copenhagen, as well as in India and the Philippines, says Karoline Bragstad.

In its latest weekly report FHI writes that BA.2 shares 38 mutations with BA.1 which is the original strain of omicron. In addition to these, BA.2 has 27 other mutations, but BA.1 only 20.

“It is thus an even more mutated edition of omicron than BA.1”, the report states.

The new subgroup is not detected in a standard pcr test.

By week 52, only about 400 cases of the subgroup had been confirmed in a laboratory in the world. But the dark figure is probably large because BA.2 lacks a genetic abnormality in BA.1 which means that the latter quickly can be identified in traditional pcr tests.

– This variant is not picked up in perhaps the most used screening method for omicrons in Europe, says Karoline Bragstad.

Can be even more contagious

To find BA.2, the entire genome of the virus must be registered, so-called complete genome sequencing. It is a slower method of analysis where Denmark is a world leader and according to Karoline Bragstad, a majority of the 400 cases in week 52 were Danish.

Since then, the number has increased even more.

On January 10, 1,361 cases of BA.2 had been sequenced in Denmark. By far the most in the world so far, says Karoline Bragstad to Dagbladet.

Karoline Bragstad.

FHI fears that BA.2 may be even more contagious than omikron’s original strain.

– It seems to increase even faster than the original omikron variant. This indicates that it is even more contagious, says the department head.

There is currently no indication that the new subgroup causes more serious illness than omicron in general.

– We know very little about it because it is so early. We hope that data from Denmark will be able to tell us more about this and we at FHI will also investigate the first cases in more detail in the lab to become wiser.


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