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Covid-19 subvariant ‘Pirola’ detected in NZ – Expert Reaction

ESR has detected the highly mutated COVID-19 variant BA.2.86 – known as ‘Pirola’ – in New Zealand wastewater samples taken earlier this month.

The Omicron subvariant has been declared a ‘variant under monitoring’ by the World Health Organization, and has been gradually spreading around the world since it was first discovered in Denmark and Israel in late July.

In a statement, the Ministry of Health said there are currently no indications that it is substantially more severe or infectious than other subvariants circulating in our communities.

The SMC asked local experts to comment. 

Dr Rhys White, Health and Environment team, ESR, comments:

“In late July, a new SARS-CoV-2 variant with more than 30 extra protein-changing mutations, was identified in Denmark and Israel. It was then rapidly detected in the United States, sparking concerns about its ability to get around the immunity people get after they recover from being sick with COVID-19.

“There have been 171 reported cases of BA.2.86 worldwide, with the first in Australia on September 7th.

“The key question is how quickly will this variant grow in both our wastewater and genomic surveillance. In 2022, we saw repeated waves of cases caused by the importation of new immune-evasive or highly transmissible variants. 2023 has been a much smoother ride with no major waves. In the coming weeks, ESR will be looking closely at any growth advantage this variant may have over those currently circulating in Aotearoa New Zealand to help us predict what impact it will have on caseloads.

“Overseas, the BA.2.86 lineage has not grown as rapidly as the initial Omicron wave, though exactly how it will compete in Aotearoa New Zealand remains unclear.

“The presence of BA.2.86 serves as a reminder that COVID-19 is still a concern. People should get tested if they show symptoms and stay home if they feel unwell.

“While BA.2.86 hasn’t shown up in Aotearoa New Zealand, until now (in wastewater), we’re ready to spot it. We closely monitor clinical data and will act swiftly if BA.2.86 emerges. ESR makes sure we sequence all available PCR samples.”

No conflict of interest.

Associate Professor Siouxsie Wiles, microbiologist, University of Auckland, comments:

“As soon as the BA.2.86 (“Pirola”) variant of SARS-CoV-2 was first detected and named a variant under monitoring, our wastewater surveillance and sequencing teams have been looking out for it. They are doing incredible work, and I hope this crucial capacity is kept after the coming election.

“BA.2.86 has been found on multiple continents, which shows it is spreading internationally, so it was only a matter of time before it was detected in New Zealand.

“Experts are concerned about BA.2.86 because it has so many more mutations than the original Omicron variant; it’s as different from Omicron as Omicron was from Delta. So far, lab studies are suggesting it’s not any more infectious than the other variants currently circulating. But the UK recently released a report summarising an outbreak caused by BA.2.86 in a care home in late August. A staggering 33 of the 38 residents tested positive. Half had symptoms and one person was hospitalized.  Twelve of the care home staff also tested positive.

“There is conflicting evidence from lab studies about how immune evasive BA.2.86 could be, with some saying very and others saying it is not very different to many of the other currently circulating variants. The good news is that the updated vaccines rolling out overseas look like they will offer some protection against BA.2.86. The bad news is that we’re unlikely to get those vaccines in New Zealand until next year.

“With the weather warming up, it’s worth remembering that improving ventilation by opening doors and windows and doing more things outdoors are good ways to reduce the transmission of BA.2.86 and all the other variants that are currently circulating in New Zealand. I’d also advise people to mask up on planes and public transport and in healthcare and aged and residential care settings.”

No conflict of interest.

Professor Michael Plank, School of Mathematics and Statistics, University of Canterbury, comments:

“The BA.2.86 variant was first detected in several countries in mid August. It stands out because it has a much larger number of mutations than other variants that have taken off over the last year or so. The fact that cases of BA.2.86 popped up around the same time up in countries with good genomic surveillance suggested we might just be seeing the tip of a rapidly growing iceberg.

“That led to concerns that the variant could bypass immunity from vaccination and previous infections and spread explosively, like Omicron did when it first burst onto the scene in late 2021. However since then, although BA.2.86 has managed to get a foothold in lots of places, it hasn’t shown a major growth advantage. One hypothesis is that is might have sacrificed some of its innate infectiousness for increased immune evasion. So although it has found a bit of a niche and may eventually become dominant, it’s not currently spreading fast enough to cause a major wave.

“It is possible that a descendant of BA.2.86 or another variant could pick up mutations that allow it to spread faster. That’s why it’s important to maintain good surveillance so we can be alerted if something like this happens. And an important reminder of basic public health measures like getting vaccinated and staying home when sick. But for now it appears that the potential impact of BA.2.86 is limited by existing population immunity.”

Conflict of interest statement: “I receive funding from the Department of Prime Minister and Cabinet and the Ministry of Health for mathematical modelling of Covid-19.”

Professor Michael Baker, Director, Public Health Communication Centre Aotearoa, University of Otago, Wellington, comments:

“The arrival of the BA.2.86 subvariant in New Zealand is entirely predictable.  Since its first detection in late July, in Denmark and Israel, it has been found across the globe, so its detection here was expected given that NZ is well connected with the rest of the world.

“The good news is that the BA.2.86 ‘variant under monitoring’ is not demonstrating a markedly greater ability to cause infections – which would be shown as a growth advantage.

“The main concern is that is shows how the Covid-19 virus is still capable of big evolutionary jumps, which is a further reminder that the pandemic remains unpredictable and is certainly not over.  This new lineage represents an important new branch in the evolutionary tree of this virus that could continue to accumulate mutations that may make the virus more transmissible or harmful in the future.

“The same precautions apply: stay up to date with vaccination boosters, self-isolate at home when sick with respiratory symptoms, and try to shift meetings with other people to well-ventilated places.

No conflict of interest.

Associate Professor Dr Dianne Sika-Paotonu,  Immunologist, Associate Dean (Pacific), Head of University of Otago Wellington Pacific Office, and Associate Professor, Dean’s Department, University of Otago Wellington, comments:

“Wastewater detection results have indicated that the “Pirola” variant has arrived in Aotearoa New Zealand. This highly mutated “Pirola” variant of the SARS-CoV-2 virus is one of the newer strains of the virus, and currently classified by the World Health Organization (WHO) as a ‘variant under monitoring.’

“Also known as BA.2.86, Pirola carries a very high number of mutations on the spike protein, which is how the virus gets into our cells.

“According to the US’s Centres for Disease Control and Prevention (CDC), the high degree of change that occurred in the virus that eventually led to the Pirola variant, is similar to the degree of change that occurred between the Delta variant and the initial Omicron variant.

“In the UK, Covid-19 cases have spiked recently prompting accelerated Covid-19 and influenza vaccination efforts for vulnerable communities and care home residents due to concerns about the Pirola variant of the SARS-CoV-2 virus.

“The impact of the Pirola variant on disease severity, hospitalization, death and potential ability to escape vaccine protection, remains to be determined.

“Staying updated with COVID-19 vaccinations and boosters, will still help prevent the worst consequences from COVID-19 such as severe illness and hospitalisation.

“Early into spring, added burden remains for hospitals, support systems, primary and community care, all continuing to experience significant pressure in Aotearoa New Zealand. These systems were overloaded prior to the start of the global pandemic, and combined with seasonal illnesses and workforce issues still causing complications, there has been additional stress and strain.

“Accessibility to Covid-19 antivirals will still be needed to reach those who require them quickly, within 5 days of symptoms, and help prevent severe illness and hospitalisation.”

No conflict of interest declared.