A person who returned from Dubai to Mangaluru in Karnataka four months ago and tested positive for the novel coronavirus, was found to have been infected with the Eta variant of the virus. The individual’s samples were sent for genome sequencing and the infection with the Eta variant was confirmed on August 5.
It should be noted though that this is not the first time a case of Eta variant of coronavirus has been detected in India, or even in Karnataka. The Eta variant was reportedly detected in two COVID-19 affected persons in Karnataka in April 2020, by the virology lab at NIMHANS, Bengaluru – which differs from the World Health Organisation’s record of when the first Eta cases were reported.
In July 2021, another case of Eta variant was confirmed from Mizoram after the National Institute of Biomedical Genomics (NIBMG) in West Bengal's Kalyani revealed the results from genome sequencing of 75 samples from the state.
Designated by the World Health Organisation (WHO) as a ‘variant of interest’ (VOI) since March 17 this year, the Eta variant or B.1.525 variant was first detected in December 2020 in the United Kingdom and Nigeria. A VOI is a variant “with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity,” according to Centres for Disease Control and Prevention (CDC).
The Eta variant is of the Pango lineage (P.1) of the SARS-CoV-2 virus, and 69 countries have detected Eta sequences in their territories. According to cov-lineages.org, there have been 168 sequences of Eta detected in India.
The Eta variant consists of the same E484K mutation found in the Gamma and Beta variants of the novel coronavirus. Beta and Gamma are variants of concern (VOC). The E484K mutation, first identified in a variant of SARS-CoV-2 from South Africa in its spike protein, is an ‘escape mutation’ – it allows the virus to go undetected by some immune defences of the human body. Dr Ravi Gupta of Cambridge University had told BBC in February 2021 that mutations like E484K do pose a threat to vaccines.
However, Eta does not carry the N501Y mutations, found in the Alpha, Beta and Gamma variants of the virus. This particular mutation gives the virus increased transmissibility. Professor Andrew Hayward, an epidemiology expert at University College London had told BBC that as of February, the B1.1.525 strain did not “seem to be spreading faster than any other strains.”
Eta stands out from other variants of SARS-CoV-2 as it has carries both E484K mutation and a new F888L mutation
VOIs can “cause significant community transmission or multiple COVID-19 clusters, in multiple countries with increasing relative prevalence alongside increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.” Scientists in various countries, including the UK, Denmark and Netherlands, are studying this B1.1.525 variant, assessing its risks to ascertain if it’s a bigger threat compared to other variants.