It’s another terrifying season.
A new offshoot of Omicron, BA.2.86 – nicknamed Pirola – has emerged in Israel, the US, South Africa and Britain after being first recorded in Denmark in late July. Pirola initially raised alarm bells because it was spotted in four countries at once – and because, after significantly curtailing our viral surveillance systems, we don’t know how long it has been circulating. Moreover, the sheer number of mutations was reason enough to be afraid: BA.2.86 has more than 30 new mutations, compared to the most recent dominant variant, XBB.1.5.
“The only other time we’ve seen such a large genetic shift was the first transition from Delta to Omicron, which led to the most hospitalizations and most deaths during each wave of the pandemic,” said Dan Barouch, head of the vaccine research. department of Beth Israel Deaconess Medical Center in Boston. As a result, scientists around the world are trying to figure out if BA.2.86 is indeed something to worry about.
Early studies suggest that Pirola, despite all its mutations, is not much better at evading immunity than previous variants. The protection that vaccines provide should last, and if you have been naturally exposed to the XBB variant, you should be better equipped to fight this new variant.
Why isn’t Pirola very good at evading immunity despite having undergone so many mutations? It is likely that it evolved from BA.2, an older, better-known form of Sars-CoV-2 that is no longer in circulation today, meaning Pirola is less resistant to neutralization than more recent variants, such as XBB.1.5. But it’s possible the variant will continue to evolve and change, Barouch warns, so staying vigilant is critical.
Determining whether it will be a success and become the dominant form of the virus in circulation will require a wait-and-see approach, Barouch added. “However, it appears that it is not spreading at the same pace as, for example, the original BA.1 or BA.5,” he says, referring to two of the Omicron variants that spread particularly quickly.
Anna Bershteyn, assistant professor and co-lead of the Covid modeling team at NYU Grossman School of Medicine, agrees: So far, so reassuring. “As far as we know, it doesn’t seem likely that this will be one of those massive waves of hospitalizations and deaths, the kind that have overwhelmed the health care system during previous epidemic waves.”
In Britain, a care home in the east of England was invaded by the variant: 33 residents became infected with Covid, 28 of whom were definitively infected with BA.2.86 – indicating that it can be transmitted quite easily. But only two hospitalizations have been reported, suggesting Pirola does not cause more severe disease than existing variants.
In certain parts of the world, its appearance has prompted action in the form of accelerated booster programs. In Great Britain, the booster kick-off was moved from October to the coming weeks. In the US, the latest round of boosters are expected to be approved by the Food and Drug Administration very soon (although who should get one remains a source of debate). The findings of a recent preprint suggest that Moderna’s XBB.1.5 booster appears to work well against the BA.2.86 variant.
But while BA.2.86 may not yet be spreading rampantly, a Covid wave is indeed unfolding, with cases increasing again. Hospitalizations are up in the U.S., though nowhere near the sky-high levels seen at this time last year. Cases are also skyrocketing in Britain and Europe.
For now, the spread of BA.2.86 appears to be nothing like the Omicron wave that swept across the world in late 2021 – the last time we saw such a large number of Covid mutations emerge. As one scientist put it, Pirola could be a “true nothingburger.”