Covid 19 Delta outbreak: NZ's tough border controls may protect against new variant - Michael Baker

By RNZ

New Zealand's border controls - widely criticised as being too stringent - place it in a unique position to keep Covid-19 variants out, prominent epidemiologist Michael Baker says.

A new strain of the coronavirus has emerged out of South Africa, prompting the United Kingdom to temporarily suspend flights from some countries.

Prof Baker says New Zealand is in a fortunate group of countries that still have tight border controls - like pre-departure tests, MIQ and self-isolation.

"The good news for New Zealand - or the reassuring news for us - is that whatever this variant does, New Zealand is well placed to manage the threat because we know that we can keep this virus out if we have to, and most countries obviously are not in that fortunate position.

"This is still a system that will be very good at picking up any infected people so we have the ability to keep out this virus if necessary - any emerging Covid-19 variant."

New Zealand's border controls remain unchanged, though the Government has laid out plans to open up, using self-isolation, from early next year.

Prof Baker said that was a different proposition to the UK, where controls have already been loosened considerably.

"Really the UK in the past has done this but they know it's only a holding action, because they're still having people physically traveling in from most of the world and people do not follow very simple travel itineraries, and viruses even less so.

"There's already, I think, a detection of this virus in Hong Kong, it almost certainly will have a very wide global distribution by now and it's just a matter of time before it's picked up in other places."

The worst-case scenario for New Zealand was that the vaccines would not be as effective at curbing the new variant, he said, but mutations would not allow the virus to evade the public health measures New Zealand has used in the past.

"Quarantine is a very simple, blunt instrument because it doesn't really matter what you're infected with - you're just kept apart from people in New Zealand for a period of time ... and you're tested along the way.

University of Otago epidemiologist Professor Michael Baker. Photo / Supplied

"The worst-case scenario is that our vaccines don't work very well on this variant, and we'd have to actually wait till people got revaccinated, or boosted with a vaccine that covered this virus."

He warned the new variant could be a problem partly because it showed a large number of genetic differences, which could indeed reduce the effectiveness of vaccines.

"They had 30 changes, which was a large number - 30 mutations of interest - so that's the first thing, and the second thing is you look at is that variant behaving differently in human populations.

"This variant appears to be increasing in incidence in the area around Johannesburg in South Africa and it's displacing the Delta variant.

"That's very unusual because the Delta variant has absolutely taken over the world because it's so infectious, and so that immediately rings alarm bells that this should be watched closely."

Variants that could evade vaccine effectiveness were also likely to become more of a problem as time went on.

"Because there's so many vaccinated people in the world ... there's evolutionary pressure favouring variants that can escape their protection to some degree."

Deputy Prime Minister Grant Robertson, speaking at the 1pm Covid-19 briefing today, said New Zealand had not had any advice to consider a ban on travel from southern Africa, but New Zealand does have a list of high-risk countries and would take advice on it.

He said the virus was a strong reminder that the global pandemic was far from over, noting that the World Health Organisation was meeting overnight and there was still some debate about the transmissibility of this variant.

Prof Baker said the WHO committee would likely report back on its assessment of the virus fairly soon.