• Chinese health and the Covid zero prison: Probation in sight or longer prison sentences for omicron sub-variants?

Studies by epidemiologists and geneticists following

SARS-CoV-2

aim to discover and analyze globally stored genome data (for example, in GISAID, the international platform for collecting sequenced

SARS-CoV-2

genomes ) to identify

the next variant

that could be worrying.

All variants circulating in the world now are sub-lineages of Omicron

.

In particular, after a few weeks of BA.2 prevalence,

BA.5 is taking over.



These days, however, the eyes of scholars are focused on a subvariant that derives not from

BA.5

, but from

BA.2

and has been

classified as BA.2.75

.

This is a variant with the potential to become of concern and therefore to be closely monitored.

It should be noted that there are still very few confirmed cases,

but apart from a larger cluster

in India

, the geographic distribution is already international (with Australia, Canada, Germany, UK, and New Zealand depositing at least one sequence), which would rule out sequencing errors.



The analysis of the variant in question was carried out in detail by

Tom Peacock

, a virologist at the Department of Infectious Diseases at Imperial College London:

BA.2.75

has 45 mutations in common with

BA.5

and 15 peculiar ones.

Among these,

8 Spike protein mutations

(BA.5 has "only" 3).

In particular, it differs considerably from the

'parent'

BA.2 with two key mutations:

G446S and R493Q.

G446S

, synthesized by scientists at the Laboratory of Protein and Virus Evolution at Fred Hutch (USA), is one of the most potent

escape sites for antibodies

induced by current vaccines that still neutralize

BA.2

.



Therefore, the forecast for BA.2.75 is for

an even greater ease in overcoming the antibody barrier

created by vaccinations or a recent

Covid

infection .

However,

G446S

will have less effect on antibodies in people with a previous

BA.1 infection.

.

Therefore, the antigenic advantage of

BA.2.75

over

BA.2

will be more pronounced in people who have not been exposed to

BA.1

.

The ability of

SARS-CoV-2

to "simulate" vaccine antibodies is increasing, also because the distance of the variants that have followed over time from the original

Wuhan

virus (on which the vaccines were designed in use) is abysmal,

the strains are very different from each other even within Omicron

: this implies greater difficulty in curbing infections, which means greater transmissibility of viruses and more people who get sick again.

On the other hand, the protection still offered by vaccines against severe

Covid

disease remains strong.

However, the success of any variant also depends on

its intrinsic transmissibility.

Until now, the infectious capacity of

SARS-CoV-2

has always increased (making it one of the most contagious viruses that has ever appeared on the planet) and the same could also happen with the

BA.2.75

variant , which has

8 mutations

in Spike protein, but it remains a difficult variable to measure experimentally and

can only be estimated once there is enough epidemiological data

to see how it is transmitted in the human population.



Nothing is known, however, about the

greater or lesser lethality

, which is measured only in the field, in hospitals.

However, so far, the virus has not gone in the direction of increasing its pathogenic impact and it is thought that this may be the case again.



In any case, the

analysis of the sequences

remains essential to understand in which direction the

coronavirus

is moving and, above all, to plan timely interventions.

It is also important to understand which variants and features

vaccine updates

will need to focus on , which risk chasing the succession of

SARS-CoV-2

variants .

Conforms to The Trust Project criteria

Know more

  • covid 19

  • Coronavirus

  • Omicron variant

Keywords: