On many occasions it is not detected in PCR tests, which has increased concern.
As a new version of the omicron variant of the coronavirus, dubbed ‘BA.2’, has been detected in more than 40 countries and is spreading rapidly, the World Health Organization (WHO) this week urged authorities to investigate its characteristics to determine if it poses new challenges for nations.
Cases of contagion with the subvariant, dubbed ‘brother’ or ‘son’ of omicron by the media, have been detected in the US, Australia, India, the Philippines, Singapore, the UK, Norway, Sweden and Denmark, among others.
“Research on the characteristics of BA.2, including immune escape properties and virulence, should be a priority independently and in comparison” with the original version of omicron, called ‘BA.1’, Maria Van Kerkhove stated on Twitter. , epidemiologist in charge of managing the pandemic at the WHO.
Is it more contagious?
According to preliminary data from the Statens Serum Institut (SSI), which is responsible for surveillance of infectious diseases in Denmark, the BA.2 subvariant is 1.5 times more infectious than its predecessor, although they have not detected differences in the risk of hospitalization.
Although the original lineage of omicron still accounts for 98% of cases worldwide, in Denmark, BA.2 became dominant during the second week of this January.
“There are some indications that it is more contagious, especially for the unvaccinated, but that it can also infect vaccinated people to a greater extent,” said Tyra Grove Krause, technical director of the SSI, collects Archyde.com.
For her part, Kristen Nordlund, a spokeswoman for the US Centers for Disease Control and Prevention, stated that “there is currently no evidence that the BA.2 lineage is more serious than the BA.1 lineage,” reports Cnbc.
The ‘stealth omicron’?
At the same time, the Statens Serum Institut indicated that BA.1 and BA.2 have many differences in their mutations in the most important areas.
In fact, the difference between them is greater than the difference between the original omicron and the alpha variant, which was the first major mutation to take hold worldwide.
The BA.2 version has five unique mutations in a key part of the spike protein that the virus uses to attach to and invade human cells, Troels Lillebaek, chairman of the Danish committee that conducts surveillance of the virus, told Cnbc. variants of covid-19.
Mutations in this part of the spike, known as the ‘receptor binding domain’, are often associated with increased transmissibility, he added.
Meanwhile, some scientists have dubbed BA.2 the ‘stealth omicron’ because it has genetic traits that make it harder to identify in PCR tests.
In turn, the WHO pointed out that, unlike the predominant subvariant, BA.2 “does not cause a specific mark in laboratory tests called ‘S gene target failure’, which makes it possible to resemble other versions of the coronavirus, such as the delta, in a first screening ».
However, this does not mean that it cannot be detected, but rather that it is done differently.
However, the WHO has not labeled BA.2 a variant of concern, although it has warned that new variants will emerge as omicron spreads around the world at an unprecedented rate.
“The next variant of concern is going to be more adaptive, and what we mean by that is it’s going to be more transmissible because it’s going to have to overcome what’s currently circulating,” Van Kerkhove said Tuesday.
“The big question is whether future variants will be more or less serious,” he added.
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