Super COVID-19 Mutant Strain Strikes Again, Is It Over Yet?

One thing leads to another. The neo-coronavirus has mutated again. Five new cases of Omicron BA.2.12.1 mutant strain infection have been reported in South Korea, according to a report in the South Korean newspaper JoongAng Daily on May 10. A total of six cases of this mutant strain infection have been reported so far, all of which are imported from the United States. This “super-strong version of the new crown strain,” according to Korean media, has arrived in South Korea and is 30 percent more infectious than the existing Omicron strain, and even approximately 20% more infectious than the fastest spreading BA.2 subtype strain.

 

Misunderstanding 1: It’s Not That the Virus is Super Strong Once it Mutates, But Super-strong Mutations Can Be Identified.

It’s been more than two years since COVID-19 was discovered. Many Greek letters and acronyms have been committed to memory. Since the early days of Alpha, Delta, and now BA.2.12.1, it appears that the words’stronger’ and’super strong’ have been used to describe these virus versions.

The neo-coronavirus is not actively pursuing novelty and change. Viruses change at random and indiscriminately, and the strongest are the ones that stand out in the fierce competition to infect humans. More viral variations fail to infect humans, and the virus becomes extinct. Even if they are discovered by humans by coincidence, they will eventually vanish.

Few who are fortunate enough to transform become the world’s mainstream neo-coronavirus and the primary focus of media attention.

The COVID-19 has gone through the Alpha, Delta, Omicron BA.1 and Omicron BA.2 mainstream phases. Although BA.2 continues to dominate in the majority of countries, three new ‘stronger strains’ are steadily emerging.

Image Credit: Covariants.

21K is the original Omicron strain BA.1, 21 L is BA.2, 22A is BA.4, 22B is BA.5 and 22C is BA.2.12.1, which is the new variant of Omicron that is that has lately made headlines.

BA.2.12.1 is primarily found in the United States, whereas BA.4 and BA.5 are primarily found in South Africa. Although there is a developing trend, it is not clear that the three of them will eventually replace BA.2 as the world’s leading mutant.

 

Misunderstanding 2: The Rumour About a 30% Increase in Infectivity Is Not Accurate

The three novel variations, BA.4, BA.5, and BA.2.12.1, have replaced the original variants in terms of local prevalence, indicating that they are really powerful.

For the past few weeks, BA.2.12.1 (red bar) has been encroaching on what was once BA.2’s area of influence in the United States, and is on the verge of reaching half of the infections.

 

Image Credit: CDC

BA.2.12.1′s development can be quantified using the idea of relative growth rate (RDR). Various figures throughout this time period place the RDR of BA.2.12.1 vs BA.2 at somewhere between 25% and 38%. This is most likely where the hot search’s 30% originates from.

BA.2.12.1 is not 30 percent more infectious in the strictest sense. It’s merely that, in the current US climate, BA.2.12.1 spreads around 30% quicker than BA.2. BA.2.12.1 is gradually becoming the dominant virus due to its quicker dissemination.

Faster transmission does not imply greater infectiousness, because human immunity and control strategies influence the actual ability to spread.

The R0 value is commonly used to describe a virus’s infectiousness (basic infectious number). This is the maximum number of persons who can be infected by a single virus in an unprotected environment. In a totally consistent environment, it’s a naked contagion competition.

Humans had no immunological protection and just a small influence from the physical quarantine policy in the early days of the COVID-19 outbreak, thus the varieties that made it into the mainstream were essentially the most contagious. R0 values for the original strain ranged from 1.4 to 3.8, 4 to 5 for Alpha, 5.1 for Delta, and 7 for Omicron, etc.

Following Omicron, infectiousness does not always imply the potential to spread. Because times have changed.

 

Fast Transmission Requires a Strong Immune Escape

The world’s major countries reached a high level of vaccination against the neo-coronavirus around the time of the Omicron, resulting in the formation of an active layer of protection.

The most significant shift was that Omicron effectively took down countries’ defenses, causing COVID-19 infection to spread from a small percentage of the population to practically everyone. While statistics show hundreds of millions of new infections worldwide, the much larger number of undetected and antigenically tested infections that go unreported creates a large statistical gap that 2/3 of the US population has experienced, according to estimate.

Image credit: Nature

Estimated true rate of neo-coronavirus infections in the US by age group

There is already passive universal immunity to the Neo-coronavirus, or Omicron strain, in many countries throughout the world, including the United States.

On this basis, the mutant strain’s biggest capacity to defeat its own kind and win the competition is no longer its endogenous infectiousness, but its ability to overcome immunity. The new mutant strains can only ‘win’ if they can better beat human immunity that has been refined in viral infections and has been actively protected by the vaccination.

Because of their better immunological escape potential, BA.2.12.1, BA.4 and BA.5 are beginning to replace BA.2 and the original Omicron and are predicted to become widespread worldwide. Their true infectiousness, or R0, is unknown.

Chinese researchers have been instrumental in demonstrating the immunological evasion abilities of all three.

Xie Xiaoliang’s team at Peking University has uploaded an informative study on immune evasion by a new mutant strain to the pre-print platform, expected to be published in Cell, which shows that Omicron virus can variably and specifically evade immunity from the original strain, as well as immune protection from a three-dose vaccination. The L452 mutation is crucial for immune evasion; BA.2.12.1 is L452Q, while BA.4/BA.5 is L452R.

The variant that will lead to the mainstream of the COVID-19 for a long time to come will also remain an immune evasion powerhouse.

 

Are the New Variants Good for the World?

Having just gone through a round of Omicron for all and having a new variant that evades immunity, it seems like the world won’t be better off.

The “predicted mutations”, which appear to be emerging more regularly now, are partly in the hands of mankind.

Dr. Trevor Bedford, who studies virus transmission evolution, has predicted a broad pattern of such changes in a series of neo-coronavirus forecasts that are increasingly being confirmed in the actual world.

Image Credit: Trevor Bedford’s speculations made public on 7 April

The Neo-coronavirus has a limited structure, despite the fact that there are many distinct varieties. The birth of Omicron has taken mutation to new heights, making it difficult to play around with it any longer, thanks to constant random attempts.

There will be no uncontrollable mutations, no substantial variations in pathogenicity, and only some fine-tuning to elude immunity in the short term (Trevor Bedford predicts an epidemic period of 1½ to 10½ years for Omicron). That is, after Omicron, the next major mutation, which will be named by Greek letters, will be difficult to achieve. While these fine-tunings make humans more docile, they aren’t so severe that they have an impact on society, turning it into a constant offensive and defensive war between various humans and BA.xxxxxxx.

This is also visible in the numbers for the past month for the United States and South Africa, where the number of new infections has grown again due to the new mutant strain’s influence, with many of them being repeat infections. There has been no notable increase in hospitalizations or deaths as a result of this.

Image Credit: Twitter @Eric Topol

COVID-19 hospitalizations in the United States from March 2020 until the present

Even with fine-tuning, immunological escapes continue to pose significant challenges for vaccine development.

Given the quick mutation, the specific Omicron vaccination that was issued a few months ago for Omicron BA.1 will not work, and any particular vaccine will become obsolete due to the rapid alterations.

The current technique of several vaccine boosters may provide greater results in terms of increasing active vaccine immunity (vaccines developed against the original strain are instead more resistant to the various Omicron mutations). In the future, better optimized polyvalent vaccines or the brand-new vaccines that cover all mutations should be available.

 

References:

[1] Xie X, Cao Y, Yisimayi A, et al. BA. 2.12. 1, BA. 4 and BA. 5 escape antibodies elicited by Omicron BA. 1 infection[J]. 2022.

[2] Telenti A, Hodcroft E B, Robertson D L. The Evolution and Biology of SARS-CoV-2 Variants[J]. Cold Spring Harbor perspectives in medicine, 2022: a041390.