Scientists are urging people to chill out about the threat posed by a "highly mutated" new variant of the coronavirus, saying there's little evidence yet it'll be any worse than the current dominant strain.
But one says it could potentially be a stepping stone to a variant even worse than Delta, which Director-General of Health Ashley Bloomfield said was "like dealing with a whole new virus".
The new variant C.1.2 was first detected in South Africa in May, and has since been picked up around the world - including a case found at the border here in New Zealand in June.
Its evolution was detailed in a new paper by South African scientists uploaded in August, showing it has between 44 and 59 mutations that make it different to the original SARS-CoV-2 virus that was found in Wuhan at the end of 2019 - more than any other found to date.
"There's a general concern that SARS-CoV-2 - the virus that causes COVID-19 - is continuing to have mutations," University of Otago epidemiologist Michael Baker told Newshub.
"Some of these give it an advantage... they become Variants of Interest if they display some features that potentially make them more dangerous, then Variants of Concern if they're having a negative effect on our ability to manage the pandemic."
So far there have been four Variants of Concern recognised by the World Health Organisation - you'd know them by their names Alpha, Beta, Gamma and of course, Delta. Five have been designated Variants of Interest - Eta, Iota, Kappa, Lambda and Mu.
C.1.2 most closely resembles Lambda, the paper says. But it appears to be evolving twice as fast as others.
"What all of us have been surprised about is for a long time we thought the genome was fairly stable - it was mutating slower than influenza," said Dr Baker.
"It was only late last year that some of these new variants meant the virus was getting an advantage. That was the Alpha variant that first emerged in the UK, and suddenly we realised it was a lot more infectious, but not more dangerous. Then of course we had Beta and Gamma, and now the Delta variant which appeared to emerge in India, we're realising is a huge step up in terms of the risk to humans."
Delta is not just twice as infectious as Alpha - the previous champion - infected people are also twice as likely to require hospital care.
But while C.1.2 contains mutations "associated with increased transmissibility and reduced neutralisation sensitivity" according to the paper - meaning it could be more infectious and better at evading vaccines - there's no solid proof yet that's the case.
"It is too early to determine whether or not it is likely to create major problems or indeed even take over from the Delta variant," said Adrian Esterman, chair of biostatistics at the University of South Australia, "Similar concerns were expressed about the Iota variant first detected in New York, and that was swiftly overtaken by the Delta variant… I think that we should remain calm, let the excellent South African virologists do their work, and watch carefully what happens over the next few weeks."
Since its discovery, C.1.2 has increased its share of infections in South Africa from 1 to 3 percent - but in that same timeframe, Delta "was really taking off and becoming absolutely dominant", said Dr Baker.
"It's not really outcompeting Delta there. Delta is outcompeting every variant so far across the planet."
But it's early days for C.1.2.
"These adaptations in the viral genome give the virus an advantage; to replicate faster and to avoid the immune system," said vaccine researcher Sarah Palmer, professor in the Faculty of Medicine at the University of Sydney.
"This current finding of a new variant that may be more infectious than the Delta variant underscores that we must increase our vaccination rates... The race continues between vaccines and variants."
The fact it reached New Zealand early on is concerning, Dr Baker said, "but at this point it's not a Variant of Concern.
"But - and this is I think the bigger implication - it's showing that this virus can continue to evolve, and also these viruses can share their genetic material. If this virus had what's called a recombination event with other lineages, it could create a virus that's a real concern."
The more people SARS-CoV-2 infects, the more chances it has to evolve.
"It is another reason why we should do everything we can to stamp out the Delta outbreak in New Zealand," said Dr Baker.