key: cord-0774226-bcs3qtnt
authors: Kunal, Shekhar; Aditi; Gupta, Kashish; Ish, Pranav
title: COVID-19 variants in India : potential role in second wave and impact on vaccination
date: 2021-06-03
journal: Heart Lung
DOI: 10.1016/j.hrtlng.2021.05.008
sha: 8ffc854e6610ec8242bd354dcc0484d34b6f563e
doc_id: 774226
cord_uid: bcs3qtnt

nan

Prevention (CDC) as "variants of interest". 2 However, recently a variant "B.1.617" has been classified as a "variant of concern" (VOC) by the World Health Organisation (WHO). This is the fourth such variant after B.1.1.7, B.1.351 and P.1 to have been tagged as a "variant of concern" owing to its increased transmission rates and it is suspected to have been a potential contributor to the ongoing massive second wave of pandemic in India. 3 In just a few weeks, the B.1.617 variant established itself as the dominant strain in India besides spreading to more than 40 other countries worldwide.

Multiple variants for the novel SARS-CoV-2 including B.1.1.7, B.1.351 and P.1 variant have been classified as "VOC" by the WHO as these variants seem to spread more easily and quickly and have the potential to escape natural/vaccine derived immunity. 3 The B.1.617 variant, infamously and wrongly dubbed as the "Indian variant", was first reported in October 2020 from the state of Maharashtra in India. 3 It harbours two important mutations, the E484Q and L452R in the receptorbinding domain (RBD) of the spike protein, leading to increased angiotensin converting enzyme-2 (ACE2) receptor binding. This enhances the transmission capability of this variant leading to greater spread of the disease. 4 In addition, these particular mutations in the spike protein also lead to a reduced binding to the selected monoclonal antibodies hence aiding immune escape and conferring increased virulence. 4 This particular variant has been reported with three sub-lineages: B. Figure 1A ). Data from the Global Initiative on Sharing All Influenza Data (GISAID) database shows that since the beginning of April, both these sub-lineages (B.1.617.1 and B.1.617.2) together account for around 70% of the SARS-CoV-2 genomes sampled in India ( Figure 1B) . [5] [6] [7] Of these, the B.1.617.2 variant harbouring mutations such as L452R, E484Q, and P681R appears to be more important with its prevalence increasing from just 1% on 1st March 2021 to greater than 70% in the first week of May 2021( Figure 1A) . 7 These variants are not only restricted to India and have widely been in circulation among various population groups worldwide since late February 2021. 3 The emergence of these novel variants through the accumulation of multiple mutations during the second wave of this COVID-19 pandemic has further iterated the fact that genomic surveillance in the ongoing pandemic is of utmost importance.

RNA viruses including the SARS-CoV-2 owing to their error-prone copying mechanisms can mutate at a faster rate. This can lead to the emergence of multiple variants in a single individual, some of which have a survival advantage in terms of greater affinity to the host receptor, faster replication rates and ability to evade the host immune response. 1 Eventually, natural selection among the genetically diverse viral population leads to emergence of newer and more lethal variants of SARS CoV-2. 1 There are various problems associated with the emergence of viral variants ranging from diagnostic difficulties, varied symptoms, rapid spread with impact on the disease severity and outcomes. Immunity either natural or following vaccination may not be protective against these novel variants which makes the concept of herd immunity or protective seroprevalence questionable. A major concern regarding the emergence of new variants is whether the available vaccines will be equally efficacious against these variants. COVID-19 variants can notoriously evade the immune response induced by the vaccines leading to infection (asymptomatic/symptomatic) and further bolstering the spread of the disease. This was highlighted in a recent report wherein two fully 

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Convergent evolution of SARS-CoV-2 spike mutations, L452R, E484Q and P681R, in the second wave of COVID-19 in Maharashtra

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We gratefully acknowledge all the Authors from the Originating laboratories responsible for obtaining the specimens and the Submitting laboratories where genetic sequence data were generated and shared via the GISAID Initiative, on which this research is based.