Eris: Everything we know about the EG.5 covid-19 variant and its symptoms

The number of recorded coronavirus cases are on the rise around the world, including in countries such as the UK, US and China. Last week, the World Health Organization (WHO) named an omicron subvariant called EG.5, or “Eris”, as a variant of interest, directing governments to keep a close eye on it. Here’s what we know so far.

What is EG.5?

EG.5 is a descendant of the SARS-CoV-2 omicron variant, which was first recorded in November 2021. It is closely related to XBB.1.9.2., another omicron subvariant, but has an extra spike protein mutation. It was nicknamed “Eris” by T. Ryan Gregory at the University of Guelph, Canada.

The subvariant also has an offshoot, dubbed EG.5.1, which contains an additional spike protein mutation.

EG.5 was first reported to the WHO on 17 February and was placed under monitoring on 19 July. On 9 August, after growing recorded EG.5 case numbers, the organisation designated it – along with EG.5.1 – as a “variant of interest”, advising health authorities to carefully monitor its transmission.

Where has EG.5 been identified? And how prevalent is it?

Globally, reports of EG.5 have been surging. In the week ending 23 July, 17.4 per cent of all sequenced SARS-CoV-2 cases were identified as EG.5, compared with just 7.6 per cent in the previous month.

As of 7 August, EG.5 cases had been reported to the Global Initiative on Sharing All Influenza Data by 51 countries, including China, the US, Australia and Japan.

“EG.5 is gradually taking over as the dominant variant in many countries,” says Brian Willett at the University of Glasgow, UK, replacing its closely related subvariant XBB.1.16.

In the US, the Centers for Disease Control and Prevention estimates that EG.5 is responsible for around 17 per cent of its SARS-CoV-2 cases, making it the fastest growing and most common version of SARS-CoV-2 in the country.

Meanwhile, the UK Health Security Agency estimates that around 14 per cent of SARS-CoV-2 cases in England are EG.5.

Does EG.5 cause more severe illness than previous variants?

The WHO has evaluated the health risk posed by the EG.5 as being low and similar to that of other omicron subvariants.

“We don’t detect a change in severity compared to other omicron subvariants,” Maria Van Kerkhove at the WHO said in a press briefing on 9 August.

Is it more contagious? And does it evade vaccines?

EG.5’s extra spike protein mutation gives it a transmission advantage over previously dominant variants, says Willett. The same mutation also affects how antibodies neutralise the virus, which may enable it to evade immunity brought about by a prior SARS-CoV-2 infection or vaccination, he says.

What are EG.5’s symptoms? How long do they last?

Like with other SARS-CoV-2 variants, EG.5 most commonly causes fever, cough, fatigue and a loss of taste or smell. It can also cause a sore throat, headache, aches and pain, diarrhoea, rashes and eye irritation.

EG.5’s symptoms last no longer than any other SARS-CoV-2 variant or subvariant, generally resolving within one to two weeks in mild cases.

How can we protect ourselves against EG.5?

For those who are particularly at risk of covid-19, such as older people and those with compromised immune systems, it is important to keep up with vaccine doses. In the UK, for example, the Joint Committee on Vaccination and Immunisation has recently announced that “at-risk” groups will be vaccinated in the coming months.

“Levels of immunity are waning as it is now some time since most people were vaccinated or boosted,” says Willett. To avoid infection, the general advice of regular handwashing still applies, he says.

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