The extremely transmissible omicron variant is being replaced in the world by a subvariant, BA.2, also known as “silent omicron”.
Until mid As of March, the most common variant on the planet was BA.1, which surprised experts due to its level of transmissibility, although it was less dangerous than others.
But already the WHO (World Health Organization) said that subvariant BA.2. almost represents the 55% of cases sequenced.
Infections, which were rapidly declining everywhere after Unimaginable daily highs caused by omicron, rose again in Europe in recent weeks, and according to the director of the WHO European division, Hans Kluge, it is due to the BA.2 lineage.
This Tuesday, the United States Centers for Disease Control and Prevention (CDC) reported that about 50% of new covid cases in the country were due to BA.2. This means that it is already the dominant variant in the country.
Given this, the Food and Drug Administration (FDA) also authorized this Tuesday a second booster dose of the anticovid vaccine for people from 50 years or more from four months after receiving the first booster.
In Asia there has also been a rebound in cases detected daily from mid-February.
“Silent” subvariant
BA.2 is often referred to as a “silent” subvariant silent,” because it does not have the genetic marker that researchers had been using to quickly determine whether an infection was most likely to be with the “regular” omicron (BA.1), rather than the delta variant.
As with other variants, a BA.2 infection can be detected by a lateral flow test or PCR, but these tests cannot distinguish BA.2 from delta. Other tests are needed to be sure.
Although a BA.2 infection can detected by a swab, scientists must perform further tests to identify the subvariant.
BA.2 is more transmissible than normal omicron although, fortunately, it is not more serious.
But how worried should we be about this variant?
Below we will tell you what is known about it.
What is BA.2?
As viruses mutate into new variants, they sometimes divide or branch into sublineages. The variant delta, for example, consists of 200 different subvariants .
The same thing happened with omicron, which includes the lineages BA.1, BA.2, BA.3 and B.1.1.549.
It is not clear where it originated, but it was first detected in November among sequences uploaded to the database from the Philippines.
Has been designated as a “variant under investigation” by the British health authorities, which means that they monitor it closely but do not worry them too much.
Although the vaccines are less effective against it and the protection d decreases over time, a booster dose increases protection and prevents hospitalizations and deaths, according to data from the UK Health Security Agency.
Is the BA.2 most contagious?
A study of 8.500 households and 18.000 persons carried out by the Danish ISS , which has not yet been peer-reviewed, found subvariant BA.2 to be “substantially” more transmissible than BA.1.
BA.2 was more efficient when it came to infecting vaccinated people and with a third booster dose than previous variants, according to the study, although vaccinated people were less likely to transmit the virus.
While a study in the UK also found that BA.2 was more contagious compared to BA.1.
Is the BA.2 subvariant more dangerous?
There are no data to suggest that BA.2 causes more severe disease than previous subvariants of omicron.
Experts assure that this subvariant is now infecting more due to the relaxation of the measures containment in many countries.
As with previous variants, experts maintain that vaccines will remain highly effective in preventing severe illness, hospitalizations, and death.
However, this subvariant is a reminder that the virus continues to cause harm to unvaccinated people, to those who have not rec given booster doses or to the most vulnerable.
“ it is still a big public health problem and it will continue to be so,” said Mark Woolhouse, an epidemiologist at the University of Edinburgh (Scotland), according to the agency Reuters.
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