The omicron variant of SARS-CoV-2, the virus that causes COVID-19, has now been round for greater than a yr. Earlier than omicron turned dominant, there had been a fast succession of named variants of concern – from alpha, to beta, to gamma, to delta. However now it appears as if we’re going through a endless string of letter and quantity combos denoting the youngsters and grandchildren of omicron: BA.2, BA.2.75, BA.5, BQ.1, BF.7, XBB – the record goes on.
So what does it take for a brand new variant to earn a Greek letter for a reputation, and are we ever going to see omicron changed?
Learn extra:
XBB and BQ.1: what we learn about these two omicron ‘cousins’
By the use of background, the World Well being Group (WHO) introduced in Might 2021 that key variants of SARS-CoV-2 can be assigned names from the Greek alphabet, along with their scientific designations.
The intention was to offer the general public a easy approach to speak about them and in addition to keep away from stigma. SARS-CoV-2 variants have been beforehand referred to relying on the place they have been first detected.
What makes a variant?
When a virus equivalent to SARS-CoV-2 replicates, it makes copies of itself. This course of is a bit like copying a doc with out a spell checker – it ends in typos.
These errors would possibly result in modifications within the amino acids that make up a protein, altering its construction or perform. These proteins kind both the structural structure of a virus or a few of the equipment wanted for the virus to duplicate.
Normally, these errors or “mutations” within the structure or equipment weaken the virus. Often although, they render the virus higher in a position to trigger illness, unfold, or evade our immune system. When viruses with the identical set of typos are present in sufficient hosts, that group is known as a variant.
So long as SARS-CoV-2 continues to unfold, it is going to hold evolving and new variants will proceed to emerge.
Unending omicron
Genetic surveillance identifies SARS-CoV-2 variants which have the potential to be extra transmissible, higher evade our immune system, or trigger extra extreme illness. These are categorized as variants of curiosity or variants of concern. The WHO has designated 5 variants of concern with Greek letter names up to now.
On November 26 2021, B.1.1.529 was recognized as a variant of concern by the WHO and renamed omicron. At the moment, omicron demonstrated a drastic shift within the virus’ evolution, with double the variety of mutations within the spike protein (a protein on the floor of SARS-CoV-2 which permits it to connect to our cells) in contrast with alpha and delta.
It was this dramatic genetic change, coupled with its larger capability to transmit between folks and evade prior immunity, that prompted the WHO to call omicron as a variant of concern.
As of now, omicron is the one variant infecting folks. Alpha, beta, gamma and delta are all now categorized as “beforehand circulating” variants of concern.
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Whereas there are genetic variations between omicron’s youngsters equivalent to BA.2 and BA.5, and its grandchildren XBB and BQ.1, they’re all fairly related to one another and the unique omicron pressure. That’s why they’re thought-about descendants of omicron fairly than their very own distinct variants.
Some scientists have argued that from a public communications standpoint this technique may do with a rethink. Particularly, they consider the excessive bar the WHO has set for brand new variants of concern needs to be lowered to allow the general public to comply with how COVID remains to be altering.
The seek for pi
Omicron’s continued dominance can largely be defined by its elevated capability to unfold between folks, and its capacity to evade prior immunity from an infection and vaccination. It’s troublesome for a considerably completely different virus to compete in opposition to omicron and set up itself.
Scientists globally proceed to watch the evolution of SARS-CoV-2, although that is turning into more durable as a result of testing and surveillance efforts have been scaled again.
The following variant of concern can be named pi, the letter after omicron within the Greek alphabet. For pi to be designated, there would should be a big distinction within the genetic sequence in contrast with omicron, and the variant must be considerably extra infectious or trigger extra extreme illness.
This new pi variant would possibly come from animals. Whereas there are few documented instances of animals spreading COVID to people, a distinct host species can permit completely different mutations to develop.
Alternatively, pi would possibly develop inside an immunocompromised host. SARS-CoV-2 has demonstrated a capability to mutate rapidly in clinically weak folks whose immune techniques battle to clear the virus, permitting it time to develop a lot of mutations.
What subsequent?
All viruses change over time and SARS-CoV-2 isn’t any completely different. Extra variants of concern will possible be named, though it will most likely sluggish.
Maria Van Kerkhove, the WHO’s technical lead on the COVID pandemic, has beforehand recommended that when we run out of Greek letters, new variants is likely to be named after star constellations. This hasn’t been formally confirmed, however one factor we do know is that this isn’t prone to occur any time quickly.