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Explainer

What we know and do not know about C.1.2: The 'most mutant of all mutant variants' of COVID-19 found to date

Mutation rate of C.1.2 seen as 'nearly twice as fast' as other known variants



The C.1.2 variant has mutated substantially more than any other known COVID-19 variants, according to latest study.
Image Credit: Twitter/Gulf News

Highlights

  • C.1.2 infection numbers have consistently risen on a monthly basis.
  • It is currently found in at least 7 countries.
  • Experts don’t know its exact transmission, severity or 'immune escape' properties yet. 

The C.1.2 variant of the SARS-CoV-2 virus was first identified and sequenced in May 2021 in South Africa. It has now infected people in several countries. Scientists found C.1.2 has mutation rate that is nearly "twice as fast" as the rate of the other variants, including Alpha, Beta and Delta.

Here's what we know so far:

How fast does it mutate?

This C.1.2 is a very fast-moving variant, say researchers. A study published in the pre-print biology server Biorxiv shows that the C.1.2 lineage has a mutation rate of about 41.8 mutations per year. That’s nearly twice as fast as the current global rate of other variants.

Image Credit: Twitter

Fast rate of mutation: What does it show?

 

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C.1.2' short period of increased evolution was also seen with Alpha, Beta and Gamma variants, suggesting that a single event, followed by a spike in cases, drove faster mutation rates, say experts.

Its ability to mutate faster than the variants of concern/interest means that C.1.2 has somehow mutated so far that it is now the "furthest mutated" variant found to date. It is more mutations away from the original virus (Wuhan 1.0) than any other variant detected so far worldwide. "It has mutated the greatest genetic distance from the original Wuhan 1.0 strain — and implies potential troubles for 1.0 vaccines," said Harvard epidemiologist Eric Feigl-Ding.

Is the number of cases of C.1.2 infections rising?

Yes. The number has consistently rises on a monthly basis, according to a study was published by South Africa's National Institute for Communicable Diseases.

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The study found a consistent rise in the number of C.1.2 genomes in South Africa month-on-month — rising from 0.2% of genomes sequenced in May to 1.6% in June and then to 2% in July — similar to increases seen with Beta and Delta variants there.

Image Credit: WHO / Seyyed dela Llata / Gulf News

In which countries is C.1.2 now present?

It was sequenced from patients in at least seven countries:

  • South Africa
  • UK
  • Switzerland
  • Portugal
  • China
  • Mauritius
  • New Zealand

What is the C.1.2 variants rate of mutation, and what does it mean?

Harvard epidemiologist Dr Eric Feign-Ding explained that the mutation rate of C.1.2 being “nearly twice as fast” refers to how quickly it gained mutations over a short period. It won’t necessarily continue to — but it certainly did in the time of window that it took to emerge.

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Image Credit: Twitter

Does C.1.2 escape immunity, or current COVID vaccines?

C.1.2 is ”worrisome” for immune escape. To explain, the authors gave the variant's technical mutation details. With C.1.2, it has a 1.7x to 1.8x faster mutation rate than the average of all other variants. The study authors note this coincides with the em ergence pattern of other really bad VOC variants.

The study stated that more than half (about 52%) of the mutations in the spike region of the C.1.2 sequences have previously been seen in other VOCs and VOIs. The mutations N440K and Y449H, which have been associated with escape from certain antibodies, have also been noticed in C.1.2 sequences.

IMMUNE ESCAPE
The ability of a fast-mutating virus to infect people who had developed immunity to it through previous infection, or vaccination.

“Immune escapes” could mean more people who have had COVID-19 remain susceptible to reinfection, and that proven vaccines may, at some point, need an update.

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So far, none of the known variants of concern or variants of interest appear to have become resistant to COVID-19 vaccines, said vaccinologist Philip Krause, who chairs a WHO working group on COVID-19 vaccines.

The not-so-good news is that the rapid evolution of these variants suggests that if it is possible for the virus to evolve into a vaccine-resistant phenotype, this may happen sooner than we like.

- Philip Krause, chair of the WHO working group on COVID-19 vaccines

“The not-so-good news is that the rapid evolution of these variants suggests that if it is possible for the virus to evolve into a vaccine-resistant phenotype, this may happen sooner than we like,” he adds. That possibility adds to the urgency of putting good surveillance in place to detect such escape variants early on, biostatistician Natalie Dean of the University of Florida told the journal Science in a January 2021 article.

What does this mean?

The scientists stressed that the combination of these mutations — alongside changes in other parts of the virus — likely help the virus evade antibodies and immune responses, including in patients who have already been infected with the Alpha or Beta variants.

What is the so-called 'festival variant'?

It is a Delta sub-variant that has emerged after 5,000 young people were infected from attending a music festival in Cornwall attended by 53,000 people. It is linked genetically to a Delta subtype. The region now has the highest COVID19 rate in England.

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It was traced because phylogeneticist can identify where it came from by genetic changes in the code. While it is being referred to among hospital staff in Devon and Cornwall as the “festival variant”, it is believed to be a new strain of Delta rather than an entirely new variant.

What does the emergence of C.1.2 show about vaccinations?

Dr Feigl-Ding noted that Delta came from India, with very few vaccines but high past infection rates; and so did C.1.2 from South Africa, which also has a very low 8% fully vaccinated rate, but large past waves.

"Hence these new super variants did not come from high-vaccinated countries. Thus, for those claiming vaccines are a major cause of these super bad variants — they are dead wrong. Unfettered spread of the coronavirus is what gives the virus more chances to practice in our bodies and learn to adapt against a body with no ready vaxxed immunity. "

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