Informally referred to as Eris, the new strain descends from the lineage of XBB.1.9.2, and would pose relatively less public health risk, compared to XBB.1.16 and the other currently circulating VOIs, based on available evidence
EG.5 strain descends from XBB.1.9.2. (Credit: Fusion Medical Animation on Unsplash)
The World Health Organization (WHO) has classified the new Covid-19 strain EG.5, together with its sub-lineages, prevalent in the US and China, as a variant of interest (VOI).
Informally referred to as Eris, the new strain descends from the lineage of XBB.1.9.2, which has the same spike amino acid profile as the XBB.1.5 sub-variant.
First reported in February this year, Eris was designated as a variant under monitoring (VUM) by the WHO, on 19 July 2023.
The EG.5 variant is found spreading rapidly in the US and has also been detected in China, South Korea, Japan and Canada, among other countries.
WHO said that the global prevalence of EG.5 has been steadily increasing, reaching 17.4% for the week ended 23 July 2023, compared to 7.6% for the week ended 25 June 2023.
Based on the available evidence, EG.5 would pose a relatively less public health risk, compared to XBB.1.16 and the other currently circulating VOIs, said the UN health agency.
WHO, in its statement, said: “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 have been observed in countries such as Japan and the Republic of 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.”
Emerged in December 2019, the Covid-19 virus affected more than 6.9 million lives worldwide, with more than 768 million confirmed cases.
WHO declared the Covid-19 outbreak a pandemic in March 2020 and ended the global emergency status in May this year.
In response to the new variant, WHO and its Technical Advisory Group on SARS-CoV-2 Evolution (TAG-VE) made several recommendations to mitigate the severity of EG.5.
WHO urged the countries to share information on the growth advantage of EG.5, and conduct tests using human sera and EG.5 live virus isolates.
Also, the agency recommends the countries perform a comparative evaluation to detect changes in rolling or ad hoc indicators of severity.
Furthermore, WHO and its Technical Advisory Group on Covid-19 Vaccine Composition (TAG-CO-VAC) will assess the impact of variants on the performance of Covid-19 vaccines.
WHO Covid-19 technical lead Maria Van Kerkhove said: “EG.5 had increased transmissibility but was not more severe than other Omicron variants.
“We don’t detect a change in the severity of EG.5 compared to other sub-lineages of Omicron that have been in circulation since late 2021.
“The absence of data from many countries was hindering efforts to fight the virus. About a year ago, we were in a much better situation to either anticipate or act or be more agile. And now the delay in our ability to do that is growing. And our ability to do this is declining.”