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The BA.2 homicron
The extremely transmissible Omicron variant is being replaced worldwide by a sub-variant called BA.2, also referred to as “silent Omicron”.
Until mid-March, the most common variant on the planet was BA.1, which surprised experts with its level of transmissibility, even though it was less dangerous than the others.
But now the World Health Organization (WHO) has said the BA.2 subvariant accounts for nearly 86% of sequenced cases.
Infections, which were falling rapidly everywhere after the unimaginable daily spikes caused by Omicron, have risen again in Europe in recent weeks, and according to the head of the WHO’s European division, Hans Kluge, this is due to the line BA.2.
On Tuesday, the US Centers for Disease Control and Prevention (CDC) reported that around 55% of new Covid-19 cases on US soil were due to BA.2. This means that it is now the dominant variant in the country.
In response, the Food and Drug Administration (FDA), the US drug agency, also authorized a second booster dose of the Covid-19 vaccine on Tuesday for people aged 50 or over, starting at four. months after the first booster.
In Asia, there is also a peak in cases detected daily since mid-February.
Why is-the called “silentX“?
BA.2 is often referred to as the “silent” subvariant because it lacks the genetic marker that researchers used to quickly determine whether an infection was more likely to come from the “normal” Omicron (BA.1) than of the Delta variant.
As with the other variants, BA.2 infection can be detected by a lateral flow test or by PCR, but these tests cannot distinguish BA.2 from delta. Further testing is needed to be sure.
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Although a BA.2 infection can be detected by swab, scientists must perform other tests to identify the subvariant.
The BA.2 variant is more transmissible than normal Omicron but fortunately not more severe.
But how much should we worry about this variant?
Here’s what we know about him.
What is the BA.2 variant?
When viruses mutate into new variants, they sometimes split or branch into subspecies. The Delta variant, for example, consists of 200 different subvariants.
The same happened with omicron, which includes subvariants BA.1, BA.2, BA.3 and B.1.1.529.
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The omicron variant has a mutation called BA.2, which is 30% more contagious than the original.
It is not known exactly where it originated, but it was first detected in November among sequences uploaded to a database in the Philippines.
This sub-variant has been described as an “under investigation variant” by UK health authorities, meaning they are watching it closely but are not overly concerned.
Although vaccines are less effective against this disease and protection declines over time, a booster dose increases protection and prevents hospitalizations and deaths, according to data from the UK Health Security Agency.
Is BA.2 more contagious?
An ISS Denmark study of 8,500 households and 18,000 people, which has not yet been peer-reviewed, found that the BA.2 subvariant was “significantly” more transmissible than BA.1.
According to the study, BA.2 was more effective at infecting vaccinated people and with a third booster dose than previous variants, even though vaccinated people were less likely to transmit the virus.
A UK study also found BA.2 to be more contagious than BA.1.
Iand subvariant BA.2 is-the more dangerousX ?
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UK health authorities have described the BA.2 as an “investigation variant”, meaning they are watching it closely but are not overly concerned.
There are no data to suggest that the BA.2 subvariant causes more severe disease than previous Omicron subvariants.
According to experts, this subvariant is now infecting more due to the easing of lockdown measures in many countries.
As with previous variants, experts say the vaccines will remain highly effective in preventing serious illness, hospitalizations and deaths.
However, this subvariant is a reminder that the virus continues to harm unvaccinated people, those who have not received booster doses or the most vulnerable.
“Coronavirus remains a major public health concern and will continue to be,” said Mark Woolhouse, an epidemiologist at the University of Edinburgh, Scotland, according to Reuters.