One of the United States' top doctors says New Zealand has a unique opportunity to create an "immunity wall" against COVID-19, but time is running out.
Eric Topol, a scientist and cardiologist, holds such sway in the US medical community he almost single-handedly stopped the Trump administration from authorising vaccines before they were tested for safety - the President wanted them out early to boost his chance of reelection.
Speaking to University of Auckland staff and students via Zoom on Wednesday, Dr Topol said the Delta variant of COVID-19 would "be the only strain in the world pretty soon", so New Zealanders better get their jabs as soon as possible.
"Delta's changed the whole calculation and I don't think people have gotten that yet. A place like New Zealand, which is naïve to Delta and basically to the coronavirus, if it does get going there, it will go really fast, and lead to a vicious spread.
"So I think this is why you are in a powerful position - if you can get close to 100 percent you will have an immunity wall that's extraordinary, and I hope that you'll be able to get close."
Polls show only about 70 percent of Kiwi adults say they'll definitely get the jab. Another 20 percent are on the fence, and 10 percent don't want it at all.
The Delta variant is about twice as infectious as the original strain of COVID-19 first detected in China a year-and-a-half ago, and can infect vaccinated people. Modelling by Kiwi researchers has suggested we'd need at least 97 percent coverage across the whole population - including children - to stop outbreaks.
Others have since said it appears there is no 'herd immunity' level for Delta, at least with the current vaccines, which were developed to fight the original strain of the SARS-CoV-2 virus. They are still very effective at preventing death and serious illness thankfully, but many Kiwis are either ineligible (too young) or can't have the vaccine for medical reasons.
From September, every Kiwi 16 or older will be eligible for the Pfizer/BioNTech vaccine forming the backbone of the New Zealand rollout. Several other countries have approved it for kids as young as 12 - and Pfizer has said it will seek authorisation to use it in five to 11-year-olds by the end of September, and infants down to six months "shortly thereafter", The Atlantic reports.
Dr Topol said getting jabs into kids' arms will be vital for stopping Delta.
"We could have gotten away if we had Alpha (first found in the UK), Beta (South Africa) or Gamma (Brazil), 70 or 80 percent vaccination rates… but now we need close to 100 percent. This is the most important thing, we need the children - they'll be the vectors, if not infected themselves."
Delta has shown an increased ability to infect children compared to other variants, and they are also far more likely to fall ill.
"We have to get the whole planet as close to the max, pushing the 8 billion mark," said Dr Topol. "We can't do that before 2023. Most countries are not as good at closing their borders as New Zealand and others to prevent the spread."
One key advantage New Zealand has over the US according to Dr Topol is our science-based approach to fighting outbreaks. Despite a quick and early start, the US vaccine rollout is stagnating - only half of Americans have had both jabs, and the rate new jabs are being delivered has levelled off dramatically. New Zealand is currently vaccinating people four times quicker than the US, per capita.
That's despite a widespread outbreak that has killed hundreds of thousands of people.
Dr Topol said the problem was the pandemic had become politicised, frequently taking shots at the Trump administration's incompetence and priorities and shaking his head when asked about anti-vaxxers spreading misinformation.
He said it was impossible to reason with people in "red states", referring to parts of the country that voted for Donald Trump over his Democrat challenger, Joe Biden. Many who had the sense to get vaccinated are still putting others at risk by refusing to wear masks, he said, failing - or refusing - to understand how much more infectious Delta is.
"We have shot ourselves in the foot big time, here. Who would have ever thought we wouldn't unite against this enemy and work together? Who would have thought this would divide us worse than ever?"
On Thursday, the day after Dr Topol gave his talk, the Government outlined how New Zealand might reopen to the world - including different levels of isolation for vaccinated people, depending on where in the world they've been, and lengthening the recommended gap between doses from three to six weeks.
"Most immunologists would agree that if you space it longer it's better – if you can," said Dr Topol.
But with Delta just "a plane flight away", as one local expert recently put it, it's also important to get as many people fully vaccinated as possible, as soon as possible.
New Zealand's elimination strategy, hailed worldwide, has given us that "luxury" - provided we don't have an outbreak.
The reason the gap was only three weeks to begin with was purely down to the speed at which the vaccines were developed.
"The bad part of the 10-month compression schedule, the 'warp speed', was three weeks as a dosing interval… They were trying to go so fast they shortened the interval from optimum.
"If you know that Delta's coming to New Zealand next week, you just want to get everybody fully vaccinated, because one dose is not going to help much. If you have the luxury of time, then I'd go for the spacing – that's the key."
Beyond the next six months, Dr Topol expects us to need boosters every six months or so, at least until a universal vaccine - one that can effectively fight all the variants - is developed. On that front, he's optimistic. SARS-CoV-2 doesn't mutate as quickly as the likes of HIV and the flu.
"I do think we'll get that next year. So my sense is between the containment, the better vaccine, the boosters, mass vaccination, we will get to a better state next year."
The full chat with the University of Auckland's Professor Chris Bullen can be viewed here.