Covid-19 Pirola variant likely to fade out, say experts

Also known as BA.2.86, Pirola has been spreading in Denmark, Israel, South Africa, Switzerland, the UK and the US

Pirola, the new Covid-19 variant, has so far been found in Denmark, Israel, South Africa, Switzerland, the UK and the US. Photo: Reuters

Case numbers of a new coronavirus variant are likely to increase over winter but ultimately the virus will fade away, a leading expert has said.

The emerging BA.2.86 or Pirola variant of SARS-CoV-2 is also unlikely to cause more severe symptoms than other circulating versions.

The World Health Organisation (WHO) and the US said last month that it was closely monitoring variant, which has so far been found in Denmark, Israel, South Africa, Switzerland, the UK and the US.

Paul Hunter, a professor in medicine at the University of East Anglia in the UK, who has been one of the most prominent scientific voices during the pandemic, said that the new variant may have been "silently spreading" in countries that carry out little testing for weeks or even months.

Prof Hunter told The National that BA.2.86 had more than 30 mutations compared to its ancestor, the BA.2 variant, which caused a wave of infections.

However, he believes that the new variant is unlikely to avoid existing immunity, whether from vaccination or prior infection.

"I don't believe we'll find it's any more virulent or cause any more severe diseases," Prof Hunter said.

"It will probably increase for a while before it will fade out. Whether that drives up a huge number of infections, it's difficult to say. But probably not in my view, but we will see."

Spike in infections

Prof Hunter said infections will likely rise in the last quarter of the year, regardless of whether there are any new variants, adding that infections will peak in November, December, January and February.

The increase in infections, he says, is likely in parts of the northern hemisphere where the temperature drop in winter means that people spend extra time indoors and are more likely to catch and pass on pathogens.

Laboratory tests analysing Pirola have indicated that it's unlikely that the variant will escape immunity.

Prof Hunter said that while BA.2.86 was likely to become more common in the immediate future, it would also probably fade away just as quickly.

"That's what happens with every new variant: it starts off, looks really impressive, then a couple of months later it peters out," he said.

New variants are likely to multiply and spread more easily because people's pre-existing immunity would find it marginally harder to recognise them than pre-existing variants, he added.

However, as this advantage declines, the new variant no longer spreads faster than others. At the same time, evolution results in the creation of yet more new variants.

Increased analysis of variants

FL.1.5.1 is another variant that is causing about 15 per cent of infections in the United States. According to reports, it may be more effective at evading existing immunity than BA.2.86.

Ian Jones, a professor of virology at the University of Reading in the UK, said that there was an argument that the continued detection and detailed monitoring of variants was "find out more than you need".

"In years gone by, we wouldn't even know they were variants because the sequencing would not be done," he told The National.

The crucial factor, he says, is whether the new variants can cause severe symptoms.

"Will it lead people to be off work or lose their lives? The answer to that – a consistent downwards from the original strain – is no," he said.

While new vaccines have been formulated to cope with new variants, Prof Jones said that there had only been a few such updates, highlighting the way that the new variants were vulnerable to pre-existing immunity.

In August last year the US Food and Drug Administration (FDA) approved what is called bivalent vaccines from Moderna and Pfizer-BioNTech.

They are designed to provide protection against both the original version of the virus and the Omicron variant.

Reformulated vaccines aimed at providing immunity against XBB.1.5, known as Kraken, a subvariant of Omnicron, has been developed by Pfizer-BioNTech, Moderna and Novartis, and are set to be rolled out soon.

Moderna said this week that trials indicated that its vaccine against Kraken was likely to provide good protection against Pirola too, Reuters reported.

It comes after comments from both Moderna and Pfizer made last month that their Kraken vaccine also provided good protection against the Eris variant or EG.5.

"Certainly [the vaccine manufacturers] are not falling over themselves to change the vaccine with the latest variant, which tells you something," Prof Jones said.