Could these Covid-19 subvariants lead to a new wave?

It’s been almost two years since the highly contagious Covid-19 first came to the fore and literally wreaked havoc all over the world. With the passage of time, several variants of the original virus in the form of Alpha, Beta, Gamma, Delta, Mu, Epsilon, Theta, Zeta, and Omicron and their respective sub-variants have undoubtedly caused great harm to people around the world.

Also read: Omicron: everything you need to know about the new COVID-19 variant
Omicron BA.4 - BA.5 New variant

The World Health Organization (WHO) has already confirmed Omicron, the B.1.1.529 line of SARS-CoV-2, as a variant of care (VOC) at the end of November 2021. During this designation, Omicron mainly consisted of three sister lines, which are BA.1, BA.2, and BA.3, each of which differs from each other in terms of mutation. While the variant BA.3 remained relatively rare, the other two became the only ones contributing to yet another surge in Covid-19 cases worldwide, with BA.2 becoming the predominant. They even led to vaccine breakthrough infections (infection in fully vaccinated people) in most countries.

Also Read: COVID-19: Understanding Facts About the Stealth Omicron Variant – BA.2

Earlier this year, in April 2022, researchers from South Africa first identified two more sister lines of the Omicron variant through their genome sequencing efforts that were later referred to as BA. 4 and BA.5 by the Phylogenetic Assignment of Named Global Outbreak (PANGO) network. Although the positivity rate of Omicron cases gradually decreased in South Africa and around the world, the latest variants led to an increase in Covid cases not only in South Africa but also in other countries, which rose slowly as the dominant variants and replaced by the other variants of Covid-19.

Here’s everything you need to know about the BA.4 and BA.5 subline of the Omicron variant:

How are the BA.4 and BA.5 different from the original Omicron Sister variants?

Several types of research on the latest variants confirm that the BA.4 and BA.5 sub-variants have a huge growth advantage over both BA.1 and BA.2, either because of their ability to transfer their ability from one person to another more quickly. escape vaccination acquired immunity.

Although BA.4 and BA.5 are quite different from both BA.1 and BA.2, they share an identical spike protein and differ from the parent line mainly by three mutations and one deletion. That said, these mutations also share many common features with the BA.2 variant, one of the dominant variants of concern around the world. Of the three different mutations found in BA.4 and BA.5, one of the mutations found in each of their spike proteins is L452R, which is believed to be responsible for the high infection rate of both BA.4 as BA.5 .

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What is the L452R Mutation?

The L452R mutation is defined as the change in the genome code at position L452R. This mutation has also been seen in Delta, Kappa and Epsilon before and is known to enhance the virus’s ability to enter human cells. These mutations have already been confirmed to be responsible for faster infectivity and transmission rate and the ability to escape neutrality by monoclonal antibodies. Preliminary research even suggests that the BA.4 and BA.5 lines may even be competent enough to evade the immunity acquired by the previous BA.1 line that causes breakthrough infections.

Are the BA.4 and BA.5 variants a threat in India?

The existence of the BA.4 and BA.5 subvariants was first identified in India on May 22 by the INSACOG (Indian SARS-CoV-2 Genomics Consortium), surfacing cases in Tamil Nadu and Telangana came. The cases were first discovered in two patients from Telangana and Tamil Nadu respectively. While one of the patients who tested positive was a 19-year-old woman from Tamil Nadu, the other was an 80-year-old man from Telangana. Both patients were fully vaccinated, had no travel history and showed only mild clinical signs.

According to the WHO, another mutation in the spike proteins of both subvariants, namely the F486V mutation, is detected as one of the largest escape mutations for other Omicron subvariants, meaning it makes the BA.4 and BA.5. descendants who are better able to evade the antibodies from previous infection or vaccination. Due to this ability of the BA.4 and BA.5 subvariants, the European Center for Disease Prevention and Control (ECDC) reclassified the Covid-19 BA.4 and BA.5 Omicron lines as Variants Of Concern (VOC), making it no longer Variants Of Interest (VOI).

dr. Rajeev Jayadevan, a noted epidemiologist and co-chair of the Indian Medical Association (IMA), says that since the BA.4 and BA.5 sublines are quite similar to the earlier mutations of the Omicron, there is a good chance that a new massive wave of infection in India is the bare minimum. This is mainly due to the high levels of hybrid immunity that have been achieved and about 90 percent of the total vaccination coverage, which is much more than that of South Africa.

Moreover, since we already have experience with the BA.4 and BA.5 subvariants from other countries, it can be assumed that there is no correlation between these variants with increased infection severity, hospitalization or death rate.

With the current data in hand, it can be concluded for now that there is no need to panic, but researchers should continue genomic sequencing to identify more new variants that may still be of concern. However, one must also follow safety protocols and precautions to stop the spread of infection altogether.

Source: https://www.who.int/activities/tracking-SARS-CoV-2-variants

https://www.who.int/news/item/22-02-2022-statement-on-omicron-sublineage-ba.2