COVID 'Pirola': What we know as scientists track 'highly mutated' variant

James Hockaday
Coronavirus molecule
It's still too early to tell the full impact of BA.2.86, but scientists are on alert. (Getty Images) (Olga Siletskaya via Getty Images)

What's happening? A new COVID variant causing concern among scientists due to its high number of mutations has been found in more countries.

BA.2.86 has now been detected in Switzerland and South Africa in addition to Israel, Denmark, the US and the UK, according to the World Health Organization (WHO).

The update comes after the US Centers for Disease Control and Prevention (CDC) warned the subvariant may have a higher potential for causing infections in those who have previously contracted the virus or received vaccination.

COVID cases have been on the rise globally, with the WHO previously warning about another variant known as EG.5 or “Eris”. The Zoe Health Study, led by King's College London researchers, now predicts that over a million people in the UK have symptomatic COVID-19.

This could potentially be pushed up further by BA.2.86, although for now it is only thought to account for a small number of cases, and it remains uncertain if it leads to more severe illness compared to other strains.

The UK Health Security Agency (UKHSA) confirmed a case of BA.2.86, saying it was undertaking a "detailed assessment" to find out more, with researchers hoping to understand more about the variant, nicknamed "Pirola" in the coming weeks.

In the worst-case scenario, scientists warn there could be "a big new wave of infections", with some countries announcing autumn boosters in an attempt to subdue a potential surge in infections.

Here, Yahoo News UK explains what you need to know about the recently discovered COVID strain.

What is BA.2.86 and why is it nicknamed 'Pirola'?

Little is known about the newly discovered BA.2.86 strain, although one thing that is concerning scientists is its large number of mutations.

Maria Van Kerkhove, an epidemiologist at the World Health Organisation (WHO), said it needs "closer monitoring", tweeting: "Surveillance, sequencing & #COVID19 reporting [are] critical to track known/detect new variants."

Scientists are concerned about the high number of mutations because it could boost the virus's ability to adapt, potentially making it both more infectious and resistant to vaccines.

As for its nickname, "Pirola", we've already had Omicron, and as the WHO are now only assigning Greek letters to variants of concern, someone has made an amalgamation of Pi and Rho, which are next in the Greek alphabet.

Where has it been detected?

BA.2.86 was first detected in Denmark on 24 July, with a second case picked up on 31 July. That same day, it was discovered in Israel.

Another case of the strain was picked up in the USA earlier this month, with a third case recorded in Ohio this week, while the UK detected its first known case in London on Friday last week.

Of course, this doesn't mean these are the only countries Pirola is confined to - it is most likely in others, too - but many countries have wound back their genomic surveillance, making it hard to tell where else it might be.

None of the cases appear to be linked, and the UKHSA said the UK case was a person with no recent travel history, suggesting a degree of community transmission within the country.

How serious is Pirola?

In short, we don't know yet.

The CDC said on Wednesday BA.2.86 may be more capable than older variants in causing infection in people who previously had COVID-19 or received vaccines.

It added that it was too soon to know whether this might cause more severe illness than previous variants.

Francois Balloux, director of the UCL Genetics Institute at University College London, said the new strain is “the most striking SARS-CoV-2 strain the world has witnessed since the emergence of Omicron” with more than 30 mutations.

To give an idea of the level of concern held by experts, the World Health Organisation has labelled BA.2.86 a “variant under monitoring”— its second tier of notable COVID variants.

Kristian Andersen, an immunologist at the Scripps Research Institute in the US, said the strain's mutations give it "all the hallmark features of something that could take off", although he added that it's too early to say for sure as "our immunity landscape is now complex".

Whatever happens, it is unlikely to cause a fresh wave of severe disease and deaths, or prompt fresh restrictions on people’s daily lives, because most people have some immunity to the illness.

Balloux, a professor of computational systems biology added: “Even in the worst-case scenario where BA.2.86 caused a major new wave of cases, we are not expecting to witness comparable levels of severe disease and death than we did earlier in the pandemic when the Alpha, Delta or Omicron variants spread."

As UCL's Clinical Operational Research Unit's Professor Christina Pagel put it: "Still plenty of potential for it to be a nothingburger but plausible *worst* case is a big new wave of infections with no intrinsic increased severity. Things will become clearer over next 7-14 days."

According to an article in the respected Nature publication, Jesse Bloom, a viral evolutionary biologist at the Fred Hutchinson Cancer Center in Seattle, thnks there is limited cause for concern. “I don’t think anybody needs to be alarmed by this,” he said. “The most likely scenario is that this variant fizzles out, and in a month, nobody other than people like me even remember that it existed.”

Nature does acknowledge, however, that researchers are "racing" to track if the new strain will be of "global concern".

What has the CDC said?

The CDC said on Wednesday the new BA.2.86 lineage of coronavirus may be more capable than older variants in causing infection in people who have previously had COVID-19 or who have received vaccines.

It said it was too soon to know whether this might cause more severe illness compared with previous variants.

But due to the high number of mutations detected in this lineage, there were concerns about its impact on immunity from vaccines and previous infections, the agency said.

The Omicron offshoot carries more than 35 mutations in key portions of the virus compared with XBB.1.5, the dominant variant through most of 2023 - a number roughly on par with the Omicron variant that caused record infections compared to its predecessor.

Read more: BA.2.86 subvariant potentially better at causing breakthrough infections: CDC (The Hill, 2 mins)

What if I've already had the COVID vaccine?

The CDC said due to the high number of mutations detected in this lineage, there were concerns about its impact on immunity from vaccines.

Professor Balloux said most people will have some immunity because they've either previously had COVID or have been vaccinated for it, but this is no guarantee.

The "bulk of vaccinations have now been some time ago, and even the most vulnerable are likely approaching the point where immune protection is fading," Professor Rowland Kao, an epidemiologist at the University of Edinburgh, told the Guardian.

He pointed to increase Covid hospitalisations (although it's not known if this is due to Pirola), and warned that seasonal factors and the "usual combination of autumn return to school and university and work" could help spread the strain.

BA.2.86 stems from an "earlier branch" of COVID, so it differs from the variant targeted by current vaccines, explained Dr S. Wesley Long, medical director of diagnostic microbiology at Houston Methodist Hospital. Although it is still unclear if it will gain a competitive advantage over rival strains.

What are different countries doing about BA.2.86?

With this additional risk of infection in mind, Europe is set for "natural experiment" of vaccination policy, with France offering a free autumn booster free to everyone who wants one, Professor Pagel said.

She added that the UK is taking a slightly different approach, restricting the offer mainly to people aged 65 and above.

Even at a local level, authorities have been taking notice of the strain's discovery, withy Buckinghamshire Council's cabinet member for health and wellbeing Angela Macpherson telling residents: "As expected, the coronavirus continues to mutate, and worldwide surveillance continues to identify new variants.

“Over the year levels of Covid in the community and therefore hospital admissions will fluctuate from time to time. The World Health Organisation says there are currently no circulating variants of concern and there is no evidence that the new variants cause more severe disease."

Meanwhile in the US, Joe Biden's government are trying to speed up the process of finalising contracts so pharmacies like CVS and Walgreens can offer free jabs to the uninsured as early as mid-September.

The CDC is keeping an eye on the BA.2.86 lineage because it has 36 mutations that distinguish it from the currently-dominant XBB.1.5 variant.

The US agency, however, said virus samples are not yet broadly available for more reliable laboratory testing of antibodies.

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