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EXPLAINED: Mu, South African C.1.2 Are The Newest Covid Variants, Here's What They Mean For Vaccines

By: News Desk


Last Updated: September 01, 2021, 14:10 IST

Experts said that vaccines remain the best bet against any Covid-19 variants even though they may display an ability to evade antibodies

Experts said that vaccines remain the best bet against any Covid-19 variants even though they may display an ability to evade antibodies

Mu was first detected in Colombia and has been reported in 40 countries. The newest South African variant is not as widespread but is under watch

As the novel coronavirus stays true to form, two new variants have emerged that are keeping health experts on high alert. One of them, B.1.621, first detected in Colombia, has alread been designated as a Variant of Interest (VOI) by the World Health Organisation (WHO) and has been termed Mu. The second, C.1.2, has been found in South Africa and displays some traits that experts say can pose worries although its spread has so far been limited. Here’s a look at both.

Why Have These Two Variants Attracted Attention?

Named per the WHO’s labelling system for variants based on Greek letters, Mu was first detected in Colombia in January this year. It was classified as a VOI on August 30 after the UN health agency noted that it “has a constellation of mutations that indicate potential properties of immune escape”.

That means it has been found to be able to dodge antibodies produced through infection or vaccination, with WHO saying that preliminary data “show a reduction in neutralisation capacity of convalescent and vaccinee sera” although it noted that these findings need “to be confirmed by further studies”.

In terms of how it prima facie looks to be able to beat antibodies, WHO said it was akin to the Beta (B.1.351) variant, which was first detected in and is now the dominant variant in South Africa that was classed as a Variant of Concern (VOC) in December last year. That is also a trait shared by the other variant that has come under the scanner, again in South Africa.

Researchers at the country’s National Institute for Communicable Diseases (NICD) said that C.1.2 — it does not have a Greek letter tag yet as it has not been designated by WHO — “shares a few common mutations with the Beta and Delta variants” but, at the same time, “the new lineage has a number of additional mutations”.

What Kind Of Mutations Are We Talking About?

Most of the common mutations that make the novel coronavirus more infectious tend to lie in the spike-like structures on its surface, which it uses to invade and latch on to human cells. Antibodies produced by the immune system after a bout infection or as a result of vaccination are geared towards detecting and disabling these spikes. A change in the novel coronavirus’s spike protein can, therefore, potentially render the virus less susceptible to antibodies because it shifts the target so to speak.

A pre-print paper on the C.1.2 variant says it “contains multiple substitutions and deletions within the spike protein, which have been observed in other VOCs and are associated with increased transmissibility and reduced neutralisation sensitivity”. Further, it flagged its “accumulation of additional mutations” as being the “greater concern”.

Where Have These Variants Been Detected?

WHO said in a bulletin that till August 29, over 4,500 samples of B.1.621 and a related variant, B.1.621.1, had been shared by 39 countries across the world. But it added that “the global prevalence of the Mu variant among
sequenced cases has declined and is currently below 0.1 per cent”, although it noted that the “prevalence in Colombia (39 per cent) and Ecuador (13 per cent) has consistently increased”.

Reports in early August said that seven residents of a care home in Belgium had succumbed to an infection caused by Mu variant. While all the seven patients were vaccinated against Covid-19, experts pointed out that some of them were already suffering from poor health.

South African researchers said that the C.1.2 has been detected in all the provinces of the country between May and August, though “at relatively low frequency (up to ~2 per cent of genomes)”. This variant has also been detected in samples from at least seven countries across Africa, Europe, Asia and Oceania.

According to online variant trackers, neither Mu nor C.1.2 have so far been detected in the samples from India that have undergone genomic sequencing.

Are Vaccines Going To Be Effective Against These Variants?

The VOI label that Mu has now received is attached to those variants that are found to have such genetic changes as are seen as being able to contribute to “transmissibility, disease severity, immune escape, diagnostic or therapeutic escape” for the virus. VOIs are also those that have been “identified to cause significant community transmission or multiple Covid-19 clusters, in multiple countries with increasing relative prevalence”. There are so far, five VOIs that have been identified, including Kappa, or B.1.617.1, that was first reported in India in October last year, around the same time that the Delta variant (B.1.617.2) made an appearance.

Delta is a VOC — one of the four at present — which means that WHO has found that it matches the criteria for designation as a VOI and further, either shows an “increase in transmissibility or detrimental change in Covid-19 epidemiology, or increase in virulence or change in clinical disease presentation”. It could also mean that it results in a “decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics”.

But the scientific and medical community is widely agreed that any vaccine provides sufficient protection against different variants of the novel coronavirus. While ‘breakthrough’ cases are not uncommon — these are people who contract an infection after having received their full vaccine dose — experts point out that the rate of hospitalisation and death for such people is much lower than that among unvaccinated individuals.

As for C.1.2, the South African researchers said that while the mutations in this lineage suggest that “partial immune escape may be possible, but despite this, vaccines will still offer high levels of protection against hospitalisation and death”.

“Vaccination remains critical to protect those in our communities at high risk of hospitalisation and death, to reduce strain on the health system, and to help slow transmission,” they stressed, adding that it has to be combined with all the other public health and social measures like “ensuring good ventilation in all shared spaces, wearing masks, washing or sanitising your hands and surfaces regularly, and keeping 1.5m distance from others as much as possible”.

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first published:September 01, 2021, 11:32 IST
last updated:September 01, 2021, 14:10 IST