Ongoing mysteries of the delta outbreak

Once a footnote in daily health updates, the number of cases that can't be linked to the greater outbreak has grown worryingly in recent weeks

Mōrena and welcome to The Bulletin for Tuesday, October 19, by Justin Giovannetti. Presented in partnership with Z Energy.

In today’s edition: A new system is coming to replace Covid alert levels; Hamilton is studying a local border; inflation is above expectations; but first, the trouble with mystery cases.

Ashley Bloomfield looks on during a press conference at Parliament (Hagen Hopkins/Getty)

The mystery count is rising rapidly. One of the numbers that underlines the scale of the delta outbreak and the challenge faced by contact tracers is the number of “unlinked cases” reported daily. Cases that scrutiny and contact tracing simply can’t link back to the greater outbreak. When the chains of transmission are well known and the tentacles of cases can be linked, the number of unlinked cases should head back to zero over time. Instead, it’s soaring.

Just over a month ago, the ministry of health began reporting how many cases remained a mystery across the previous fortnight. When Auckland was in level four lockdown, the number was hovering around a dozen per day. The number increased and dipped as new unlinked cases were detected and older ones were solved. However since the move to level three, the number of mystery cases has shot up. As of yesterday, the tally sits at 140 over the past fortnight.

What does this mean for the delta outbreak? Dr. Dianne Sika-Paotonu, an immunologist from the University of Otago, spoke with The Bulletin about what the mystery cases mean:

"Each of these cases represent potential transmission chains that are unknown and are potentially indicative of delta continuing to spread in our community. These mystery cases could have been passing on the virus and infecting people in the community without their knowledge. We continue to see these appear despite the higher restrictions,” she said.

That likely means that there’s a gap between the number of people with Covid-19 in New Zealand and the number of cases reported every day. Each mystery case could speak to a larger unknown chain of transmission. 

“We may have reached the point where people are too afraid to come forward to get tested and that might mean the number being reported at 1pm doesn't truly reflect the precise number of cases out in our communities,” Sika-Paotonu added.

It’s already impacted contact tracing. Stuff reports that the ministry of health has stopped tracking sub-clusters in the outbreak because the growing number of mystery cases has made it unwieldy. There were more than 30 sub-clusters when the count stopped, and nearly half were no longer linked. According to the ministry, the focus has shifted from trying to create epidemiological links and simply identifying, testing and isolating close contacts.

Mystery cases are also at the centre of Waikato’s lockdown. While Northland is headed back to level two, parts of Waikato will remain in level three and face more restrictions than Auckland until at least the end of the week. While newly reported cases are “broadly linked” in the area, the prime minister said yesterday, an ongoing drip of mystery cases in Waikato has raised concerns. That’s the issue with unlinked cases: if they remain a mystery after a few days, they might indicate that you don’t know as much about an outbreak as you’d like.


Thank you from The Spinoff publisher Duncan Greive: It’s a little overwhelming to be sitting here, a week on from when I wrote my Bernie-esque plea for new members, to write to you about the response. It was instant and humbling. It has been the biggest surge in new sign-ups since the freaky days of April 2020. We also saw many existing members raise their ongoing contributions, which was also hugely impactful.

To be blunt, we needed it. And still do, so if you can join up, or have been meaning to, please do so today. We are still a long way from knowing when this period will end, which means our commercial funds remain highly constrained. We remain highly dependent on our members for everything from live updates, to data visualisation to cultural coverage. But we've had a really heartening week, and the whole organisation is very grateful for it. If you are a member, or have donated—please take a moment to feel the immense gratitude radiating out from all of us here.


It’ll be another big week for the country’s fight against Covid-19. After a cabinet meeting yesterday afternoon, the prime minister announced that Auckland’s alert level won’t change for at least two weeks, according to The Spinoff’s live updates. The education minister will unveil a plan on Wednesday for reopening Auckland’s schools after nine weeks of lockdown. On Friday, a “traffic light” system will be unveiled to eventually replace the alert levels.


The Covid numbers: The delta outbreak has now surpassed 2,000 total cases. There are 30 cases in hospital and 5 in ICU/HDU. There are now 635 active cases in New Zealand. 57 new community cases were reported in Auckland yesterday and 3 in Waikato. 29,661 people were vaccinated on Sunday.

The Spinoff’s Covid data tracker has the latest figures.


Opposition is already growing to the government’s traffic light plan. Stuff reports that public health experts and Māori organisations who have been consulted about the plan have voiced their concerns. It’s a significant change from the alert levels and seems to do away with regional lockdowns completely. Vaccine certificates will feature prominently. A red light, the strictest level under the proposed setup, appears to be about a 2.5 according to the current alert levels. The key will be the level of vaccination required before the plan is implemented. The prime minister has said it will be high and some experts are calling for 95% fully vaccinated across the country.


Hamilton is studying the creation of an ‘anti-covid’ border with Raglan. The neighbouring town is a Covid hotspot and Hamilton leaders think border controls could help with the ongoing outbreak. However as the Waikato Times reports, there’s also concern in Hamilton about creating “drama” and being seen to force Raglan locals to be tested and vaccinated. The town has nearly half the cases in the region and below average vaccination levels.


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Inflation is nearly 5% and the Reserve Bank is facing calls to act. Inflation is now rising at the fastest rate since 1987, if you exclude years when the GST was hiked. Many people today have never had to think much about it, but high levels of inflation can become a personal and economic problem. If you didn’t have a 5% pay hike over the past year, and the average worker got less than half that, your buying power shrank. Stuff reports that economists want the Reserve Bank to aggressively hike interest rates to slow inflation. The rise in prices is a global phenomenon and nearly all other major central banks have pledged to let inflation run its course over the next year. New Zealand’s money hawks might be left standing alone against a torrent.


The Shaw climate plan hasn’t passed the emergency test. Writing for Newsroom, climate reporter Marc Daalder finds that a plan put forward by climate change minister James Shaw is neither ambitious nor coherent. Released last week as more of a consultation paper than an actual plan, Shaw did explain how the government intends to lower emissions across the economy. It’s unlikely the cuts would go far enough. With New Zealand’s poor climate record, there are growing concerns that trade partners might punish the country’s exports in the coming years.


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A look at the streaming wars in New Zealand. (Tina Tiller)

Right now on The Spinoff: Chris Schulz looks back at what happened when Netflix rolled into Aotearoa as part of Screen Week. Andrew Szusterman writes about the near-impossible task of creating high-rating drama on network TV in New Zealand. Justin Latif reports on how Auckland councillor Josephine Bartley is using KFC and comedy to get people vaccinated. Madeleine Chapman asks and reviews the question we all have: Was the North Shore lockdown party any good? Anne Wyllie explains why saliva testing is so special in the fight against Covid-19.


All Blacks vow to use younger players, go hard against US team. Sunday’s test in Washington DC is a brand-building exercise for rugby in the US, but the All Blacks’ coach says he isn’t worried about inflicting heavy defeat on the Eagles, according to Stuff. The last time the All Blacks played in the US the final score was 74-6.


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