Alert level D-Day: Negative wastewater result in Christchurch may be needed - expert

Prime Minister Jacinda Ardern and Director-General of Health Ashley Bloomfield. Photo: NZ Herald
Prime Minister Jacinda Ardern and Director-General of Health Ashley Bloomfield. Photo: NZ Herald
An epidemic modeller believes wastewater test results could hinder Christchurch's chances of moving down alert levels this weekend.

Cabinet meets today to decide if any areas outside of Auckland can move to a lower level.

Covid-19 was detected in Christchurch's wastewater on Saturday and Monday, but three returnees with Covid-19 are isolating in the city.

Director of Public Health Dr Caroline McElnay said on Thursday the three active cases in managed isolation in the city would show up in the wastewater testing. Samples from nearly every other wastewater catchment were negative, she said. Testing has been undertaken at 27 locations across the South Island. More wastewater testing was done in Christchurch on Thursday.

University of Canterbury Covid-19 modeller Professor Michael Plank says until that wastewater result, he thought it would be reasonable for the South Island to move down levels.

He says the government may wait until Monday to change them, on condition of a negative wastewater result in Christchurch.

Most experts are urging a few more days in lockdown across the country as part of a "cautious approach" to containing the Delta outbreak.

The Government's top adviser says while "I'd love to say Santa Claus exists" there was no easy way to stamp out Delta and there were still tough times ahead.

Prime Minister Jacinda Ardern and her colleagues have given little away ahead of today's decision, but experts say any decision comes with risk, and officials will be closely examining the potential for any spread outside Auckland and Wellington, including any contacts of cases still awaiting test results.

Other key questions will be exactly how soon the levels change and the geographic spread, with suggestions the country could be split into three regions - Auckland, the rest of the North Island and the South Island.

More than 24,000 contacts have been identified so far, including hundreds spread across the South Island. For this reason, experts urge a few more days to reach the 14-day incubation period of the virus.

Epidemiologist Dr Michael Baker said there was still a risk the virus could be incubating outside Auckland and Wellington.

Level 3 was good at containing spread, but not at eliminating the virus, Baker said.

Michael Baker. Photo: RNZ
Michael Baker. Photo: RNZ
Bar any developments, a "cautious" approach could see the South Island enter level 3 from Tuesday, meaning it had been through a full 14-incubation period since the lockdown began.

Level 3 included opening up gatherings to 10, and limited hospitality services, but still prevented large gatherings including most businesses and schools.

"It is feasible [to go to level 3] from this weekend, but carries more risk," Baker said.

It was also feasible the North Island, bar Auckland, could also be lowered to level 3 then, but there remained some risk given the 12 cases in Wellington.

The fact they were all contained in their bubbles and there had been no spread was reassuring, Baker said.

"One option could be for Wellington and/or the North Island to hold on a bit longer, and then effectively split the country into three zones with Auckland."

More information about cases that were already effectively quarantined, in their bubbles, and those that were out in the community needed to be provided, Baker said.

If there was a move down alert levels, Baker said the Government should look to carry mandatory mask use in certain crowded indoor levels with it.

'I'd love to say Santa Claus exists'

Eminent epidemiologist Sir David Skegg says he is cautiously optimistic New Zealand will get out of this outbreak - but it all depended on the community's ongoing response.

He said on current progress, he expected the country to emerge from lockdown in a few weeks.

But Skegg, the Government adviser on elimination, told Newstalk ZB's Mike Hosking that even with vaccination levels up, public health measures would still need to be maintained with Delta.

"Unfortunately there's no easy way out of. I'd love to say Santa Claus exists but unfortunately whatever we do in New Zealand we are going to have some tough times ahead."

Skegg maintained elimination remained the best option for New Zealand. "No one would have wished to have this outbreak but the good thing is that it is making people realise we need to get vaccinated," he said.

"I'm cautiously optimistic that we will get out of this but Delta is definitely a lot more infectious, it's a lot more difficult to stamp out and it really all depends on us," said Skegg.

"If we observe the lockdown better than Melbourne and Sydney have done then of course we will get rid of this in the next few weeks... I'm expecting this to happen."

Skegg praised the way politicians of all major New Zealand parties were approaching Covid, saying they were not talking down to the public and pulling the wool over our eyes like those in Australia including, he said, Scott Morrison.

"We haven't had that kind of talk-down stuff, believe me, and the elimination strategy is obviously the best option at the moment. It's done brilliantly well for the last 18 months and while we haven't got a vaccinated population it's essential."

Case numbers set to level off?

Covid-19 modeller Professor Shaun Hendy said daily case numbers should begin to level out over the next days – and then begin dropping.

Modellers wanted to see the basic reproduction number, or R0 – that's the expected number of infections in an outbreak generated by one case – fall below 1, meaning the outbreak could be stamped out.

"We had been hoping see that happen by tomorrow, but the lags in testing have probably spread that out a bit," he said. "Also, we are expecting to see more cases from within households, too – which means we'll maybe have an extended period where our numbers are flat, rather than declining.

"But I'd hope that, by next week, we'll be getting a clear signal that we're below an R0 of 1."

He said we could have optimism if no further infections were detected outside Auckland, or that were unrelated to the small number confirmed in Wellington.

"We'd be hopeful that we don't see cases in the South Island over the next while, and if that's the case, I think a shift to alert level 3 - and hopefully to level 2 not too long after that - is on the cards," he said.

"For Auckland, we don't want the scale of this outbreak getting much bigger, because of the strain that it's putting on the health system at the moment.

"So we'd like to see alert level 4 do its thing and get those daily case numbers down to single digits."

Hendy said the scale of this outbreak compared more with New Zealand's main wave then last August's community outbreak, but we now had better systems in place to manage cases.

"That means we should – assuming our systems stay intact – mop up those last cases a lot more quickly than we did last year."

A decision on Auckland's lockdown will come on Monday, but with still-rising case numbers there is a firm view among experts level 4 will continue there for potentially weeks after the Tuesday deadline.

The 68 new cases reported in the community yesterday was the highest daily number yet in the current outbreak, bringing the total to 277.

Of those, 34 people had received one dose of the Pfizer vaccine and 10 were fully vaccinated, director of public health Caroline McElnay said.

There were 263 cases in Auckland and 14 in Wellington. There was no evidence of any spread outside those two regions.

Covid-19 had been detected in Christchurch wastewater, though McElnay pointed out there were three active cases in managed isolation in the city. Samples from nearly every other wastewater catchment were negative, she said.

In Wellington, Covid-19 continued to only be detected at Moa Pt. No new results had been reported from Auckland wastewater since Wednesday.

Ardern said 16 cases had not been connected to the current outbreak, but they were probable and still being investigated.

All other cases infected since lockdown began had come from close and/or household contacts, and there was no evidence of community transmission, McElnay said.

There were 495 locations of interest - but only three new ones were added today: a pre-lockdown rugby game and two supermarket visits post-lockdown.

This all showed the lockdown was having an impact, Ardern said.

The virus hasn't spread beyond Auckland and Wellington. If it weren't for lockdown, Ardern said she was sure we would have seen cases spread further.

"With Delta, people are infectious much sooner and appear to give it more people. We can expect the lag time in our numbers to be longer and bigger," Ardern said.

There are still six sub-clusters. The Birkdale Social Network cluster has 35 confirmed cases and the Māngere church cluster has 114 cases.

Sixty-five per cent of contacts have been followed up by contact tracers and individuals were self-isolating. Seventy-one per cent of all close contacts have had a test.

Meanwhile, epidemiologist Sir David Skegg warned that the Auckland lockdown could last for weeks, and warned that life will get more difficult for people after the country reopens its borders.

"It is unlikely the lockdown will end next Tuesday, it'll be a matter of weeks I fear," Skegg said.

2000 Countdown workers off work

Countdown corporate affairs general manager Kiri Hannifin says the outbreak has hit the company across the country with staff off in supermarkets everywhere.

She said the store asked people over 70 or with immune issues to stay at home as well as those forced into isolation through Covid.

"There are people off everywhere but we're really, really heavily impacted by the visits to stores in Auckland."

She said it was great to see workers being prioritised for vaccination in the past week.

"We've 20,000 workers so to have 2000 of them off, it's hard to trade. It's pretty tough," said Hannifin told Newstalk ZB's Mike Hosking.

She said the company was not keen to redeploy staff around Auckland, but rather keep them in their work bubbles.

She said the company was doing its best to keep the situation safe reducing trading hours and putting head office administration staff into stores to bolster the ailing workforce.

"I really can't believe they keep turning up every day to keep working. It's very humbling to watch," she said.

She rejected claims prices were being hiked during the outbreak. "Not at all. No, not at all. Categorically not," she told Hosking.

She said any higher prices, especially around produce, were always connected to whether the vegetable or fruit was in season.

Pasifika vaccinations ramp up

Minister for Pacific Peoples Aupito William Sio said the community was "ramping up" vaccinations across Auckland. "Everybody's doing their part," he said.

He acknowledged that there was some failing in the messaging to the Pacific community about Covid. "Look, there's no system that's 100 per cent," he told TVNZ. "We're focused on getting people tested."

He said frontline workers and church leaders were "getting on with it" and that was reflected in the growing number of vaccines.

He responded to the "significant" criticism of the way Covid information had been disseminated to the Pasifika community.

"There's no dispute there are gaps in the system, we are learning as we go," he said.

He said there was no update on case numbers, repeating the daily message from MPs that any new information would be delivered by the Prime Minister at the daily briefing.