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Scientists scrutinise characteristics of new Omicron sub-variant

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Studies are underway to find out the specific features of the latest Covid-19 variant ‘BA.2’. It is already responsible for most of the recent cases in a number of countries, including India, Denmark and Sweden. But for French Health Minister Olivier Veran, the arrival of this sub-variant in France is not a “game changer”.

BA.2, nicknamed “Omicron’s younger brother”, made its debut in France a few weeks ago. First mentioned by Veran during a press conference on January 20, this new Covid-19 derivative is being investigated by scientists.

  • Where does BA.2 come from?

BA.2 was first introduced in late December 2021 in India and South Africa. It is a subtype, believed to be derived from a mutation of Omicron (officially known as BA.1). Omicron itself was born from the transformation of the delta. Other subtypes, such as BA.3 or BB.2, have already been cited, but due to the dramatic increase in cases of people who contracted BA.2, they have attracted less attention from epidemiologists.

BA.2 has more than 20 mutations, about half of which are in spike proteins. These are the famous proteins that interact with human cells and are the key to the virus entering the body.

  • Is this sub variant as dangerous as Omicron?

The World Health Organization (WHO), which classified Omicron as a “type of concern,” did not distinguish between it and its BA.2 subdivision at this stage. For its part, Vera said that “as far as we know at the moment, it is more or less consistent with the features we know about Omicron.” It’s not a “game changer” at this stage, Veran added in an attempt to reassure.

BA.2 is being closely studied by the scientific community, but there is no definitive data yet on its vaccine resistance or the severity of the Covid-19 case. Scientists have been cautious about this.

Tom Peacock, a virologist at Imperial College London, tweeted: “Very early observations from India and Denmark indicate that there is no dramatic difference in severity compared to BA.1. This data should become more solid (one way or another) in the coming weeks. “

Peacock added that “there is likely to be minimal difference in the effectiveness of vaccines against BA.1 and BA.2. Personally, I’m not sure BA.2 will have a significant impact on the current omicon wave of the epidemic.

“Some countries are close, or even closer to the top of the BA.1 waves. I would be very surprised if BA.2 causes another wave this time. This is not a delta-omicon change at all, even with a little more transmissibility, and is likely to be slower and more subtle instead, ”he predicted.

For Epidemiologist Antoine Flaholt, director of the Institute of Global Health at the University of Geneva, infection monitoring should make it possible to test resistance to BA.2, especially if people infected with the classic omikron are again contaminated with the sub-variant. However, the population needs to have the means to detect contamination with BA.2, which seems fragile at this stage and which does not seem self-evident.

  • Why is BA.2 difficult to trace?

BA.2 poses certain challenges for scientists, as it is not easy to track. Changes in PCR test protocols and the fact that the type of kit varies from one laboratory to another makes it difficult to reliably identify BA.2, according to Florence Debere, a biologist at the Institute of Ecology and Environmental Sciences in Paris. “In the UK, the way the tests are conducted does not allow us to distinguish between BA.2 and Delta,” Debere explains.

There is a more accurate but less commonly used tool for tracking variants: the genetic sequence of viruses. This allows to identify the exact presence of this sub variant. But in France, for example, only a few laboratory tests are randomly subjected to this more in-depth and expensive analysis. Sequencing also has the drawback of being slow, which means that it is not suitable for monitoring fast spreading variants.

  • Where is BA.2 most influential?

Sub-variants have been discovered in at least 43 countries on all continents. It is considered to be the most common type in a number of countries, including India, Denmark and Sweden. In Denmark, the number of daily cases of Covid-19 is on the rise again, while Danes thinks they have already reached the top.

The UK Health Security Agency (UKHSA) has identified more than 400 cases in Britain in the first 10 days of January.

“The Danish authorities have no explanation for the incident, but it is being closely monitored,” said the French public health agency, which is following the latest developments in Denmark. This “suggests that BA.2 is more transmissible”, Deber agreed. In Europe, the UK, Germany, Belgium, Italy and France also rank BA.2, while cases are also reported in North America, Asia and Australia.

  • Is BA.2 developing rapidly in France?

The French Public Health Agency says that to date, sub-variants have been discovered in France at “very low levels”. “We have an international situation where the omicron variant is very rotating, so it is normal that we observe sub-variables periodically,” the agency said in a statement on January 21.

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