Key questions about the origin of this outbreak remain unanswered - but we're edging closer to solving the mystery. Science reporter Jamie Morton reports.
The index case
Could this outbreak - now numbering 72 cases and more than 10,000 contacts - have started in a public thoroughfare next to an inner-city MIQ?
That's now a possibility that officials are investigating.
Here's what we know so far.
The closest we have to an "index case" - that's a "patient zero" in an outbreak - is a traveller who arrived from Sydney into MIQ at Auckland's Crowne Plaza on August 7.
They had a day-one test on August 8 and returned a positive result the next day.
This person - one of just a handful of positive cases detected at the border after New Zealand suspended quarantine-free travel with Australia last month - was then transferred to the Jet Park quarantine facility.
Later, on August 16, they became unwell and were moved to Auckland's Middlemore Hospital.
Because the hospital wasn't considered a hot-spot - the case entered care just a day before lockdown, and days after other cases in the outbreak became symptomatic - the source investigation team has cast their net around the Crowne Plaza, Jet Park and border staff involved in the person's transit.
But community transmission via border workers might now appear unlikely.
All 208 and 200 staff working at the two sites have since been re-tested and returned negative results.
"The feedback that we've had so far is that transmission to staff, and the staff bringing it into the community, at this point is almost ruled out as a possibility," Covid-19 Response Minister Chris Hipkins said today.
Back to the traveller.
They were pin-pointed as the likeliest index case by genomic test results that matched both the earliest identified cases in the community, and cases that were part of the New South Wales Delta outbreak.
Otago University virologist Dr Jemma Geoghegan remained "cautiously optimistic" about this case being the source, as we still couldn't be 100 per cent certain.
After all, while genetic data could provide clues about the transmission chain, actually proving transmission was much more difficult, even with infection from a genetically identical coronavirus.
"There are lots of genetically identical genomes in New South Wales to our MIQ 'index' and there was lots of people on those red zone flights," she said.
"So, although the genomics strongly supports a connection there are some missing pieces in the transmission puzzle."
Nevertheless, the evidence now on the table was compelling enough for officials to remove from their inquiry locations of interest that pre-dated the flight's arrival.
The Crowne Plaza
Much of the focus has centred on the Crowne Plaza - and for clear reasons.
The index case has been genomically linked to three other positive cases who were in a family bubble staying in the room next door.
As a result of the link between those cases, officials quickly put in place post-departure day five testing for returnees who were in the Crowne Plaza, and who were on the same floor and whose stay over-lapped with the infectious period of that original case.
And that the virus could have spread between rooms through aerosols shouldn't be a surprising possibility.
It's been shown to have happened in MIQ before - remember the "bin lid" inquiry? - and last week, it was reported it passed from one group of returnees in Jet Park to another, when their room doors were opened simultaneously for mere seconds.
But how might have the virus travelled from the hotel into the community?
"It could have been passed from one person to another in the facility who's then left, or during transport from the airport to the hotel," Te Pūnaha Matatini Covid-19 modeller Professor Michael Plank said.
"There are a number of possibilities."
One compelling one was a walk-through route next to the hotel's lobby, which is used as a public space and separated from the plaza by a perspex shield standing only about seven feet high.
Director general of health Dr Ashley Bloomfield said CCTV footage showed three people who had used the walkway "who were there at the point in time when this person, who we think is the source of the outbreak, was being moved in the hotel".
"The team is working with police to identify and follow up with each of those people just to see if they may be part of the existing outbreak."
If that did prove to be the way Covid-19 had escaped, it would represent an especially frustrating border failure.
Only last month, one person who went through the zone told Newsroom it was an "outbreak waiting to happen".
Hidden chain of infection
New Zealand first learned it had an outbreak on its hands last Tuesday, when it was revealed a 58-year-old man from Devonport had tested positive.
He'd become symptomatic on on August 14 - meaning the infectious period likely would have started on August 12 - and had spent August 13 to 15 on holiday with his wife in Coromandel.
It still wasn't clear how many links were in the chain of infection stretching between this man - "Case A" - and the presumed index case.
"Our contract tracers and public health units now have the hard job in piecing together this puzzle," Geoghegan said.
"The clever way in which genomics has been utilised in this pandemic is really by integrating it with the epidemiological data."
It's meant the dozens of community cases detected so far have all so far been able to be threaded back into a single outbreak, albeit one with multiple clusters.
Plank said the current hypothesis allowed the virus to spread for 10 days between the index case and its detection in Case A.
"The other possibility is that it wasn't the MIQ case, and that it's gone via another Australian state and come into New Zealand during that last gasp of the transtasman bubble, which ended around July 30," he said.
"But that seems very unlikely to me, as we'd be looking at a much bigger outbreak than what we've seen so far."
With more than 10,000 potential contacts identified so far, Plank said the priority for officials was less on the outbreak's source, and more on forward contact tracing and infection control.
"I think we're probably going to be as confident as we can be that [the traveller] was the source," he said.
"Whether we'll ever find the exact epidemiological link to other cases, I'm not sure. But we've reached the stage that the main priority is stopping transmission going forward."
Otago University epidemiologist Professor Nick Wilson said gaining the complete picture of the outbreak's origin would still be valuable for plugging gaps in the system.
"I was surprised we managed to go for six months," he said of the outbreak.
"Because Australia, despite having some tighter approaches than New Zealand, has also kept having these failures."
Modelling by Wilson and his colleagues in April, before the New South Wales' outbreak, that for both countries the failure risk for those transiting quarantine was estimated at 6.3 failures per 100,000 travellers - and 5.8 per every 1000 positive cases of the virus.
As the pandemic ground on, they warned the rate of failures might increase - something down to an increasing proportion of infected travellers from overseas, and faster-spreading new variants like Delta.
Wilson again called for New Zealand to move our MIQ system away from hotels, and toward specialised facilities like those being built in Australia.
"Hotel quarantine made a lot of sense at the beginning of the pandemic, but now we really need to review - otherwise we're going to keep having outbreaks until we're all vaccinated."