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Covid-19: BQ.1.1, BF.7, XBB.1.5... Why don't the new variants have a more precise name?

2023-01-07T17:07:11.153Z


DECRYPTION - Since June 2021, the World Health Organization (WHO) has been using Greek letters to designate the main lines of Covid-19. However, this is not the case for the latest variants in circulation.


“BQ.1.1” in France, “BF.7” in China, “XBB.1.5” in the United States… The different names of the variants of Covid-19 currently circulating in the world are enough to get us lost.

"

We should use names more suitable for the public

"

, suggested

in this regard in

Le Figaro 

Mircea Sofonea, epidemiologist and lecturer in the PCCEI unit of the University of Montpellier, then questioned about the sub-variant "XBB. 1.5” which is gaining momentum in the United States.

Why does the scientific community choose such an obscure nomenclature for laymen?

These variants, like all those currently circulating, "

descend from the Omicron variant

"

,

first of all reminds

Le Figaro

Florence Débarre, researcher in evolutionary biology at the CNRS.

Use of the Greek alphabet

To understand the non-attribution of Greek letters to current strains, we must go back to the beginning of the pandemic.

Originally, the variants were named according to their place of detection (“

English variant

”, “

South African

variant ”, “

Brazilian variant

”, etc.).

On May 31, 2021, the World Health Organization (WHO) announced that it would now use Greek letters to designate variants of Covid-19.

The aim was to have names "

easy to pronounce and remember

", but also to prevent the general public and the media from using "

stigmatizing and discriminatory

" names referring to the place where the first cases of variants were detected. , explained the WHO.

Read alsoCovid-19: what if the “worst variant” was in fact in the United States?

A new Greek letter is assigned to each new variant judged to be of concern and sufficiently different from the variants in circulation (Alpha, Beta, Delta, Omicron, etc.).

On its website, the WHO defines a variant of concern as a variant “

associated with one or more changes, which have a certain importance for public health at the global level

.

The WHO thus lists three changes: “

increased transmissibility

,

increased virulence

” and “

decreased effectiveness of public health and social measures

.

Regarding the current sub-variants, the answer remains the same.

The WHO indicates to

Le Figaro

that

“a new label, that is to say a new attribution of a worrying variant, would be given if there were a variant sufficiently different in its impact on public health, and which would require a change in the public health response.”

Which is currently not the case.

Read alsoCovid-19: could the powerful epidemic wave in China affect France and Europe?

Currently, we remain in the Omicron dynasty

, insists Florence Débarre.

BA.2 and

BQ.1.1

[respectively responsible for the sixth and ninth waves in France, Ed]

have similar properties

.

Unlike Delta and Omicron which do not have the same characteristics.

Omicron took over from Delta at the end of December 2021. "

Delta and Omicron do not come from the same branch of the family tree, they are clearly different

"

,

supports Florence Débarre.

Even if all the variants of Covid-19 have the same original strain of the virus as “

common ancestor

.

A family tree

So where do the letters and numbers used today come from?

From the Pango system, set up in 2020 by a group of British researchers and used by scientists even before Greek letters were used for Covid.

"The fundamental principle is that the names of the lineages represent the ancestry and the descent"

, explained in June 2021 to

National Geographic

Oliver Pybus, biologist specializing in evolution at the University of Oxford, who participated in Pango's design.

The latter can be read as a family tree of Covid-19.

Each branch corresponds to a line.

"

This makes it possible to trace the different generations of virus lines

"

,

explains Florence Débarre.

Pango lines work with a letter, followed by numbers.

A dot separates the letters from the numbers and the numbers from each other.

Originally, there were two main lines of Covid-19, named “A” and “B”.

Only variants from the “B” line are circulating today.

Thus, “B.1” descends from “B”.

"B.1.1.1" comes from "B.1.1", which itself comes from "B.1".

Following this same logic, “BA.1”, the first Omicron variant which replaced “Delta” at the end of 2021, is a cousin of “BA.2” or even of “BA.5”, responsible for the seventh and eighth waves in France .

Read alsoA simplified nomenclature for Covid variants

Pango lines cannot have more than three points.

If too many digits were to be added, a new letter would replace them.

For example, the original name of “BQ.1.1”, which therefore descends from “BQ.1”, is “B.1.1.529.5.3.1.1.1.1.1.1.1”.

Note that “BQ.1.1” comes from the line of “BA.5”.

“B.1.1.529” corresponds to the real name of the first Omicron variant.

The new letters are given in alphabetical order, according to the date of appearance of the sub-variants.

The X in “XBB” is used to designate recombinants, those variants resulting from the combination of two strains such as “XBB.1.5”.

“XBB.1.5” therefore comes from the “XBB.1” line, but “

it has a key mutation that the parent line did not have,

explains Florence Débarre.

Similarly, a new lineage arises when multiple mutations occur, or when a single mutation is large enough.

If the virus changes completely, the first letter may also change.

The gamma variant, detected for the first time in Brazil, was thus called P.1, although it descended from “B.1.1.28” and its name could therefore have been “B.1.1.28.1”.

Mythological creatures?

This Pango system serves as a common language for all scientists.

To promote understanding by all, some scientists use the names of mythological creatures on social networks.

"BQ.1.1" was thus nicknamed "

Cerberus

" - three-headed dog guarding the gate of the Underworld, "BF.7" "

Minotaur

" - half-man and half-bull creature - and "XBB.1.5" "

Kraken

" - sea monster with several tentacles.

"

Mythological names have been around for a long time, it's nothing new

"

,

comments Mircea Sofonea.

However, these new names are not unanimous.

"

These names have no scientific basis, they were invented on Twitter

", reacts Florence Débarre.

What bothers me is that these are mythological monsters, which can unnecessarily alarm

” the general public

, she laments

.

Read alsoThierry Wolton: “The real reasons for the abandonment of the “zero Covid” policy in China”

In September 2021, the WHO said it was considering using constellation names for future variants.

Without going any further.

Source: lefigaro

All tech articles on 2023-01-07

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