New Zealand could have looser borders now and balance that risk by being at a pseudo-alert level 2 - but the Prime Minister would rather stay at level 1 and run a tighter ship at the border.
"Our tolerance for risk is low because we are living essentially without restrictions," Jacinda Ardern told the Herald in an interview on the Covid year that was, where we are now and what we should expect in the year to come.
An alternative to the status quo is to "accept you're going to have a bit in the community but be in a pseudo level 2 environment".
"I think we've made our call. I think people are happy with that call but it does mean that the border is the thing we keep having to tightly manage."
Tourism and hospitality operators had been hoping for an influx of Australian tourists, but they will still benefit from level 1 activity as opposed to a pseudo level 2, which could have limits on gatherings and social distancing in public places.
A bubble would free up thousands of spots in MIQ, which are currently at full capacity until February 24 next year.
One of the hold-ups is disagreement on what should happen if there is a new outbreak in Australia.
The 14-day quarantine period at the border could also be loosened, given recent research showing that cases are most infectious two days before symptoms begin and five days afterwards - though some may be infectious for as long as 20 days.
The US Centers for Disease Control and Prevention is now recommending a 10-day quarantine, or seven days with a negative test.
Public health experts in New Zealand have pushed for a risk-based border system - a pre-departure quarantine and negative test and a post-arrival 14-day quarantine for those arriving from high-risk countries, and less stringent quarantine requirements for those coming from low-risk countries.
While different quarantine periods have been discussed, Ardern said 14 days remains the gold standard.
"Even with 14 days, there is a small amount of risk attached to that. With less than 14 days, there's more risk. It depends where you draw the line.
"We've had a low tolerance for risk because we don't have restrictions, and that's the trade off we've made - very tight and low tolerance for risk so that we can operate in a way that, if you have Covid in the community, it would be very risky."
'We did have to drive it really hard'
Asked what she would tell her grandkids about those early Covid days, when one unprecedented measure quickly followed another, Ardern said it was the sheer speed of how quickly things escalated.
"It was the end of February and I was in Australia when we had our first case come through into our border, and from there, in such a short space of time, we knew that 48 hours would make a difference between a full-scale outbreak and us getting things back under control."
On March 14, with six cases in the country, Ardern asked everyone entering New Zealand to self-isolate for 14 days. She then shut the borders to non-Kiwis on March 19 after it became clear the request wasn't being universally followed.
On March 21, in a national address from her Beehive office, Ardern revealed the alert level system, asking older people to stay at home and telling the rest of us we were at level 2.
Two days later, when the first cases of community transmission emerged and with councils already closing their services, she announced an immediate move to level 3 and an imminent move to level 4 lockdown.
The Prime Minister has spoken about her daily walks to and from the Beehive during that time, hearing the fear in people's conversations and seeing people loading bags of flour into their cars.
"It was only in January that I was looking at countries looking at forms of lockdown and thinking, 'Imagine asking every single New Zealander to stay home for a month. Imagine that.' And yet, we did it.
"I knew there was no 'wait and see' with Covid. Every day you could, if you get into a bad spot, just move to doubling [cases] and doubling and doubling again."
And if the lockdown call was made 48 hours later than it was?
"I try not to think about that. It's clear, and you see from what happened in other countries, those numbers can just escalate. We knew we didn't have a lot of time."
The historic measures kept coming. There was no way to check if every Kiwi coming home was self-isolating properly, so she announced compulsory managed isolation or quarantine from April 10.
"That felt huge," Ardern said, having already imposed lockdown.
"We were sending a message to the rest of the world that essentially, unless you're willing to stay indoors for 14 days, don't come to New Zealand."
At the same time, officials were scrambling to shore up contact-tracing - which could only deal with 10 active cases in mid-March, when we already had over 100 cases - and to secure the reagents needed for the PCR Covid tests.
Ardern said the ice got pretty thin, but never so thin that she thought it might break.
"Reagent was a real issue. There were some points where we had small buffers, but we had relationships to continue to make sure we had that supply. But we did have to drive it really hard - frequent phone calls directly with those in the ministry who were ordering the reagent.
"It was tough, no doubt, but there was never a point where I didn't feel there was a plan we were pursuing, so that gave a level of certainty."
State of high alert
Today there appears to be no Covid-19 in the community, again, and New Zealand has just topped the Bloomberg Covid resilience index.
But there have been frequent border incursions since the end of July and an MIQ bubble breach every 36 hours, leaving public health experts worried that a large outbreak is inevitable without further strengthening the response.
Ardern concedes that the risk of Covid leaking from MIQ into the community is objectively higher as more people come home from places that are increasingly Covid-ravaged.
About 40 per cent of MIQ beds are normally taken up by people flying in from relatively Covid-free Australia, but for December the traffic from Australia is dropping by 20 per cent as Kiwis from the rest of the world return for a summer downunder.
Of the 11,000 MIQ vouchers allocated for the month of December, roughly half of them are flying in from ports in Asia - Doha, Dubai, Hong Kong, Singapore - that commonly link New Zealand with Covid-devastated Europe. Another 1000 are flying in from Los Angeles.
How will Ardern handle the greater risk?
"It's exactly the same strategy. You've got to treat every passenger, and we have, as if they have Covid."
Asked about any additional measures, she noted the Government's summer resurgence plan - expected to be released on Tuesday - where public health units will be ready to roll out testing stations to any popular summer destination.
"So long we have Covid in the world, we will be in a position of having to be in a state of high alert. That's our job. We carry that anxiety so that the rest of the country can keep going. We need everyone to be vigilant with us, though."
Vaccine the key to lifting border restrictions
It's likely Kiwis will spend some of 2021 with the current border restrictions, while frontline healthcare and border-facing workers are vaccinated, people are still urged to use the Covid Tracer app, and Covid Cards are rolled out for those without smartphones.
How long border controls last will depend on information still unknown.
Top of that list are the vaccines: how many, how good will they be, when will they arrive, and how long will it take to vaccinate the population?
"Even with a vaccine, people might not get sick but they could still carry it and pass it on," Ardern said.
"Will we have enough data and evidence to say people with a vaccine don't pose a risk anymore (and are allowed to enter Covid-free New Zealand without quarantine) versus whether we won't have a risk because our population is by and large vaccinated (herd immunity)?"
Achieving the latter is being worked through by the Ministry of Health, including who gets vaccinated first, and how to handle those who refuse.
Getting vaccines approved and rolling them out will be a logistical challenge. The Pfizer vaccine, for example, requires two doses, which would take six months to roll out if 50,000 people received a dose every day.
It is expected to arrive in New Zealand in March but is already being rolled out this week in the UK, where the usual rigours have been bypassed in the face of tens of thousands of new daily cases.
New Zealand's Covid success means we don't have to cut such corners, and it also gives us some breathing room to see if anything goes horribly wrong overseas.
In the meantime, some form of border restrictions are likely for the next 12 to 18 months.
"It's going to be a phased approach to a point where [vaccines] will be available for everyone," Ardern said.
"But in between, we may be able to see changes at our borders. It will depend on what the research tells us about the way the vaccine is working."