The roll-out of coronavirus vaccines - when they arrive - will be one of the largest and complex undertakings in the history of public health in New Zealand. What can we say about the operation already? Science reporter Jamie Morton makes three assumptions.
Border workers are likely to be among the first in line
Here's what we know so far.
New Zealand is likely to have enough doses of a vaccine for at least 750,000 people early to mid next year.
That hinges on it passing the last stage of trials and meeting our own regulations, and more deals are being brokered with other makers that will boost our coverage.
Hundreds of millions of dollars have been parked for these pre-agreements, which are complementary to what we'd receive - that's potentially enough for half the population - through the global Covax Facility.
All the while, Ministry of Health officials are busy laying the groundwork for one of the biggest immunisation programmes in our country's history.
More than $63m has been set aside for medical supplies like needles, syringes, swabs, freezers and protective equipment.
The ministry states: "Ideally, the immunisation programme will achieve sufficient population immunity, and to ensure protection for Māori, Pacific peoples and population groups at particular risk from Covid-19."
Yet the Government hasn't said exactly who'll be first in line, as that's something that'll be determined by factors like trial data on the suitability of each vaccine for different age groups.
It's also unlikely that all of the vaccines will come at once.
Immunisation Advisory Centre director Dr Nikki Turner, whose group has been involved in preparations, expected New Zealand would likely get small amounts at first - meaning a staged approach.
"It'll be targeted, either to prevent spread or to offer direct individual protection," she said.
"We also don't know how well the vaccines will act in the first instance, or if they protect the individual only, or if they'll also be able to prevent spread.
"So, initially, it's going to be part of a range of strategies to try and reduce spread."
If New Zealand still had no virus circulating in the community come the time for roll-out, we could assume the first doses to be distributed among front-line workers like border officials and clinicians, and perhaps the elderly and those with chronic medical problems.
"But again, it basically comes down to supplies, who the vaccine would be suitable for, and what we're trying to achieve, which, initially, will probably be just to protect."
Prime Minister Jacinda Ardern speaks to a lab technician during a visit to the Malaghan Institute of Medical Research, which is involved in efforts to make a vaccine locally. Photo / Pool
University of Auckland vaccinologist Associate Professor Helen Petousis-Harris said there was a good chance the vaccine just secured - an mRNA candidate made by global drug giant Pfizer and German biotechnology company BioNTech - would be effective in older people.
"Right now, the RNA vaccines are looking like they're able to induce a nice immune response in older people, and the trials are now including that cohort," she said.
"So it's reasonable to think the vaccines might be used early in them, because we'll have the data."
How many people would need to be initially targeted?
According to Census figures, more than 700,000 Kiwis are older than 65, and around 170,000 are aged over 80.
There are also around 3000 people working in managed isolation and quarantine facilities and about 100,000 practising clinicians like doctors, nurses, dentists and midwives.
There's a clear reason to prioritise front-line healthcare workers.
Almost 100 of them were infected with Covid-19 while they were doing their jobs during New Zealand's first outbreak - equating to 10 per cent of all local cases.
Infectious diseases expert Associate Professor Siouxsie Wiles said another cohort to potentially target were people in their 20s, 30s and 40s.
Over the first part of New Zealand's pandemic experience, these age groups made up more than half of local and imported cases.
People aged between 15 and 54 also comprise just over half of our population.
"They're the ones who are more likely to pick it up and spread it - and once it gets into the younger population, it gets into the older population," Wiles said.
One new Australian study that modelled scenarios in 179 countries, and published before peer review, suggested that prioritising people aged between 30 and 59 could potentially halve vaccine requirements.
But Wiles stressed our vaccination priorities would likely be different to that of other countries.
"Because we don't have widespread transmission, we won't be immediately trying to stop deaths in the most vulnerable - we are trying to stop any transmission or incursion."
It was our country's Covid-free status and good healthcare system that initially had Government officials concerned New Zealand could be placed down the pecking order if the global vaccine roll-out was allocated by need.
The roll-out will require a massive education campaign
Even if we get enough vaccines, would people actually be willing to immunise?
A recent Massey University survey indicated about three quarters of Kiwis intended to - that's a higher rate than the US (64 per cent), the UK (53 per cent) and Germany (61 per cent) - and half would even if pay if they had to.
But it revealed some clear ethnic differences that planners will have to build into their campaign to get more buy-in.
For instance, more than a third of Māori respondents said they wouldn't get it, compared to an overall decline rate of 26 per cent.
People were worried about possible side-effects and getting inadvertently infected - trials and rigorous MedSafe checks will obviously negate these risks - as well as testing being rushed to get vaccines out fast.
The survey indicated a lack of trust could be a problem, as could belief in conspiracy theories.
Associate Professor Nikki Turner - director of the Immunisation Advisory Centre at the University of Auckland - expects the vaccine roll-out to be a staged process. Photo / Mark Mitchell
"There'll be a lot of different issues when it comes to communication," Turner said.
"One is maintaining trust in the strategy, and that the vaccines that we'll bring into New Zealand will have gone through proper, appropriate, safety regulatory processes before they get here."
Wiles agreed that buy-in would be a major issue.
"How do you get everybody who needs to have it to take it? That's going to be a big one, because the Government has made very clear that they're not going to make it mandatory," she said.
"I think that's absolutely the right call to make. We don't need to do something much more heavy-handed, because when it comes to vaccines, it's all about building trust.
"But what we have to be mindful of is that there are very active forces that are spreading false information, and that is going to ramp up."
The Advertising Standards Authority has already upheld one complaint - against Advance NZ and the New Zealand Public Party - for making false claims about "mandatory" Covid-19 vaccines.
The problem isn't new. Misinformation about vaccines has hampered immunisation efforts for years.
One recent snapshot by Otago University researchers found half of Facebook pages about vaccines were negative, although most generated by Google and published on YouTube were positive.
As it stood, New Zealand had generally high immunisation coverage rates, but Wiles said we couldn't assume that would mean high uptake of the Covid-19 vaccine.
"We are going to have to be absolutely clear that data from the trials are transparent, so that people know they are getting a safe and effective inoculation."
It will be a mammoth logistical effort
Will we have enough people trained to give the vaccines?
Turner believed so, even though she didn't expect the entire population to be vaccinated at once.
"We are ramping up work around getting vaccinators trained, and ensuring we've got a large enough pool of them, despite the fact we don't yet know exactly what sorts of vaccines we'll be getting," she said.
"Much work needs to be done to make sure that our distribution is effective as possible, so we can get reach the right people."
The Ministry of Health is also working fast to rebuild the National Immunisation Register, which would prove a crucial resource.
"It'll tell us who's been vaccinated, and who's still yet to be, so it'll be a really important tool alongside all of the other primary care databases."
"Obviously, it's all going to be a big exercise, but, we're not inexperienced. It'll be different from previous campaigns, but New Zealand has done many of them before."
One of the most recent has seen more than 300,000 people vaccinated against HPV since a nationwide effort kicked off in 2008.
A campaign against meningococcal disease, launched in 2004, also managed to halt within three years an epidemic that killed nearly 250 Kiwis.
Associate Professor Siouxsie Wiles says the key to a successful roll-out will be Kiwis showing the same unity and patience that resulted in our effective Covid-19 response. Photo / Arvid Eriksson
"In this case, we're not sure what formulation the vaccines will come in - and the temperature requirements they will need to be transported in, what we call a cold chain."
Typically, vaccines in New Zealand must be kept between 2C and 8C at all times during storage and transport.
Yet some of the new-generation candidates we're likely to get require much colder temperatures - or even -70C, when it comes to the mRNA vaccines.
"It basically requires liquid nitrogen," Wiles said.
"So you can begin to imagine how much more complicated the cold chain becomes. How do we bring in and distribute a vaccine that needs to be kept at -70C?
"Right now, it's definitely one of the big things being looked at."
Ultimately, Wiles believed the key to a successful roll-out would be Kiwis showing the same unity and patience that resulted in one of the most effective Covid-19 responses in the world.
"So much work is going on behind the scenes to prepare for this. And if mistakes are made, we shouldn't think of them as failures, because this is difficult," she said.
"We need to remember that compassion and kindness has got us this far through the pandemic.
"We'll need it for the vaccine stage when our health system will be doing its best to protect us."