What is the difference between the Covid Pirola and Eris variants? everything you need to know

New variants of Covid continue to spread around the world as experts warn that cases will rise as the summer ends.

Three strains of Omicron have emerged that exhibit significant mutations from the original variant.

The arrival of Eris, Pi and more recently, Pirola, coincides with unsettled weather and a “small but significant” increase in hospital admissions in England.

It comes as the UK has seen 93,083 new cases of Covid up to September 3, according to The Zoe Health Study.

The UK Health Safety Agency (UKHSA) said Covid-19 cases and ICU admissions continued to rise in its latest update, while hospital admission rates have increased in most age groups.

Here's everything you need to know about the new Covid variants:


Pirola, or BA.2.86, is the latest Omicron variant to appear this summer, with 34 more mutations than BA.2, according to virologist Professor Lawrence Young.

According to the Centers for Disease Prevention and Control, on August 23, two cases of BA.2.86 were identified in the US.

One of the cases is in an individual traced through the CDC's Traveler-Based Genomic Surveillance, and the “identification of these cases in multiple geographic areas is evidence of international transmission,” the CDC said.

However, the CDC noted that current hospitalizations in the country are “not likely” to be driven by BA.2.86, but added, “this assessment may change as additional data become available.”

Globally, the variant has been identified in Denmark, South Africa, Israel, the UK and the USA.


A descendant of Omicron, Eris, or EG.5.1, was first classified as a variant by the World Health Organization (WHO) on August 9. It is the second most common variant in the UK after Arcturus, XBB.1.16, and the most common variant in the US, according to the Centers for Disease Control and Prevention (CDC).

Eris was initially put on watch on 3 July 2023 due to increased reports internationally, particularly in Asia, the UKHSA said.

According to Professor Young, a key difference for Eris from other Omicron variants is that it has an additional mutation (F456L) in the spike protein “which may be due to its ability to evade the neutralizing antibody response from previous Omicron infections”.


The Pi, or BA.6, is another variant of the Omicron. It has only been sequenced so far in Denmark and Israel since July 24.

Head of primary care and public health at Imperial College London, Professor Azeem Majeed said the variant “is not currently found very often in people infected with Covid-19”.

Professor Christina Pagel told Sky News that although it is “very, very early”, Pi has “a lot of new mutations that make it very different from previous Omicron strains”.

The arrival of Eris, Pi and more recently Pirola coincides with unsettled weather this summer in the UK

(PA file)

What are the symptoms?

All three variants are strains of Omicron. According to the ZOE Health Study, the five most common symptoms of Omicron are:

  • Catarrh
  • Headache
  • Fatigue (mild or severe)
  • Sneeze
  • Sore throat

However, three more commonly reported symptoms are diarrhoea, eye irritation and rashes, Young Scientist.

How worried should we be?

said Professor Young The independent he said new mutant variants “compete with each other and continue to change as they spread.”

He added: “We are already seeing an increase in symptomatic Covid infections and a small but significant increase in hospitalizations due to Covid.

“It is very likely that we will see waves of infection in the winter. The hope is that, with various mitigations, including fall vaccine boosters with updated XBB series mRNA vaccines, these will be small waves.”

Prof Majeed said that despite “concerns” the new variants would be able to “evade immunity and cause more severe disease than previous variants”, previous immunity from vaccination and infection “continues to provide good protection to more people”.