The World Health Organisation (WHO) declared new COVID-19 strains 'Eris' or EG.5 a "variant of interest" (VOI). "Formerly a variant under monitoring, WHO has now designated this a variant of interest," the global health body said in a tweet late Thursday. The WHO said there has been a steady increase in "this variant’s prevalence", adding that "over 7,000 sequences have been shared from 51 countries as of August 7", 2023.
What is a 'variant of interest'?
SARS-CoV-2, the coronavirus which causes COVID-19 disease, continues to evolve. Multiple variants of concern (VOCs) and variants of interest (VOIs) have been designated by the WHO based on "their assessed potential for expansion and replacement of prior variants, for causing new waves with increased circulation, and for the need for adjustments to public health actions", the global health body says.
A "variant of interest" is when the virus has undergone a change with suspected implications. According to the US National Institutes of Health (NIH), VOIs are defined as variants with specific genetic markers that have been associated with changes that may cause enhanced transmissibility or virulence, reduction in neutralisation by antibodies obtained through natural infection or vaccination.
Simply put, "when a variant of interest emerges, it says, 'Oh, this is something we should watch a little bit.'," a report quoted Chicago Department of Public Health Commissioner Dr Allison Arwady as saying.
As per the Centers for Disease Control and Prevention (CDC), variants designated as VOI include variants that have:
> Predicted increase in transmissibility or disease severity.
> Reduced neutralisation by antibodies generated against previous infection or vaccination.
> Reduced efficacy of treatments, or tests.
> Changes to receptor binding domain (RBD).
As compared to a "variant of interest", a "variant of concern" is a variant in which there is evidence of an increase in transmissibility of the infection, more severe disease, a significant reduction in neutralization by antibodies against the virus and reduced effectiveness of treatments or vaccines.
Currently circulating variants of interest (VOIs) as of August 9, 2023:
> XBB.1.5 : Recombinant of BA.2.10.1 and BA.2.75 sublineages
> XBB.1.16 : Recombinant of BA.2.10.1 and BA.2.75 sublineages
> EG.5
What is Eris and when was it first reported?
EG.5 or Eris variant of SARS-CoV-2 was first reported on February 17 this year, and designated as a variant under monitoring (VUM) on July 19.
The COVID-19 variant, EG.5, is a descendent lineage of Omicron subvariant XBB.1.9.2. It carries an additional mutation in the spike protein — which the SARS-CoV-2 uses to enter and infect the human cells — compared to the parent subvariant.
Other countries which have reported 'Eris' COVID variant
As of August 7, 7,354 sequences of EG.5 have been submitted to GISAID, the Global Initiative on Sharing All Influenza Data, from 51 countries.
The largest portion of EG.5 sequences are from China (30.6 per cent, 2,247 sequences). The other countries with at least 100 sequences are the US, the Republic of Korea, Japan, Canada, Australia, Singapore, the UK, France, Portugal, and Spain, news agency PTI reported.
In India, only one case of EG.5 has been reported so far from Pune in Maharashtra in May this year.
How severe 'Eris' COVID variant is?
In its risk evaluation report, the WHO noted that while EG.5 has shown increased prevalence, growth advantage, and immune escape properties, there have been no reported changes in disease severity to date.
While concurrent increases in the proportion of EG.5 and COVID-19 hospitalisations (lower than previous waves) have been observed in countries such as Japan and Korea, no associations have been made between these hospitalisations and EG.5.
However, due to its growth advantage and immune escape characteristics, EG.5 may cause a rise in case incidence and become dominant in some countries or even globally, the global health body said earlier.
(With inputs from PTI)
First Published: Aug 11, 2023 9:59 AM IST
