Covid 19 coronavirus: Shift to Level 2 'not cautious enough' - expert

Health experts have responded to the Government's move to lift Auckland's lockdown at midnight with a mix of optimism and worry, with one arguing the step isn't cautious enough.

"We still don't have any clear idea how the pandemic virus got through the border and many test results are outstanding," said prominent epidemiologist Professor Nick Wilson, of Otago University.

He argued it would have been more prudent to have shifted Auckland to an alert level "2.5" with mandated mask use in indoor public places and workplaces, and tightened borders around Auckland.

Wilson advocated a "targeted zone" around Auckland, with restricted movement in and out of the region, potentially with only the exception of life-threatening emergencies.

His colleague, respected epidemiologist Professor Michael Baker, today made that same call.

Wilson said that, ultimately, New Zealand was seeing far too many preventable border failures, with 11 since August.

"Australia is also having a notable border failure rate – despite superior processes in hotel-based quarantine when compared to New Zealand."

He said this highlighted a need to turn down the tap by restricting arrivals from designated "red zone" countries that were badly infected.

"This could be only allowing in humanitarian cases after appropriate both pre-flight testing and pre-flight quarantine."

Wilson thought vaccination of border workers would almost certainly help.

"But much more needs to be done including getting MIQ facilities out of Auckland, tightening processes in MIQ facilities, and mandating use of QR codes located at potential super-spreading settings such as bars, nightclubs, gyms and churches," he said.

"Enabling the Bluetooth function on the app should also be mandated for all border workers.

Otago University epidemiologists Professor Michael Baker (left) and Professor Nick Wilson argue that a shift to an "alert level 2.5" would have been a safer move. Photo / Supplied

"Without improvements in all these areas it seems likely there will continue to be border failures every few weeks, while we wait to get widespread vaccination of the New Zealand public."

This evening, Baker said he'd feel more comfortable with the alert level change if it had been used to roll in a more "sophisticated" approach to the tiered systen.

"The alert level system needs to be updated to reflect new knowledge about how easily Covid-19 is transmitted in indoor environments - and how the alert level system is now being used in a more nuanced and geographically targeted way."

Baker saw the need for sub-levels, like 1.5 and 2.5, to make mask use requirements clear, better describe limits on indoor gatherings, and manage movements outside of geographic areas where there was higher risk of Covid-19 transmission.

"Using this updated approach, Auckland could then shift to alert level 2.5 and the rest of New Zealand to alert level 1.5," Baker said.

"Doing this would help to avoid the high level of complacency that sets in when we move down the alert levels."

Infectious diseases expert Associate Professor Siouxsie Wiles was also hesitant about the jump.

"It's no secret that I would have preferred for Auckland to stay at alert level 3 for a couple more days until all the test results had come back," she said.

"But, the decision by the Government to move Auckland to alert level 2 and the rest of the country back to alert level 1 suggests they are confident the outbreak is under control and any further transmission can be limited using the test-trace-isolate strategy."

No doubt, she said, the rapid move would also signal to Kiwis that the Government would only use the more restrictive alert levels when needed - and for as short a time as possible.

"With this news, it's very important that New Zealanders continue to be vigilant for any symptoms of Covid-19 and get tested as soon as possible to ensure that any cases of the virus in the community are identified as soon as possible," she said.

"This has always been important, but is even more so with these newer more infectious variants of the virus.

"I really hope that the small size of this outbreak doesn't lull anyone into a false sense of security regarding these new variants."

Otago University epidemiologist Dr Amanda Kvalsvig added that, despite some reassuring results, stepping down alert levels did introduce risk, given there was less protection against unknown transmission from potential earlier missed cases.

But there were also many positives to note.

"As demonstrated with the Auckland August cases, an outbreak can still be controlled even if the original case is never found," she said.

"New Zealand now has a superb testing and contact tracing system, with people working around the clock and great uptake from the school community.

"We also have a Prime Minister whose understanding of the principles of outbreak control is extremely impressive and on today's evidence, well up to postgraduate level.

"This ability to ground decisions in evidence and transparency in communicating how decisions are made is a key element of New Zealand's elimination strategy."

Otago University infectious diseases expert Professor David Murdoch said the decision showed officials felt the extent of the potential spread had been contained.

"[It shows] there is confidence that all of the close contacts are either being tested or contained at the moment."

But there was still some concern and uncertainty, he said, given there were still test results to come in, and the source of the scare remained unknown.

"I think it will be a cautious and probably nervous time over the next few days as we see the rest of the results - and hopefully we don't have any more cases."

Covid-19 modeller Professor Michael Plank, of Canterbury University and Te Punaha Matatini, said it was reassuring that test results had virtually all come back negative.

"So overall, it's looking pretty good."

But, despite clear assumptions that today's new cases were likely secondary infections from the initial ones, Plank was still concerned at the lingering possibility that transmission could have instead come from them.

"It's not completely clear to me, from the information that we have at the moment, that we can say definitively either way," he said.

"But I would add that Dr Bloomfield said that cases D and E were asymptomatic - and that's good news.

"Because if they're asymptomatic, it means they're less likely to have been the source of transmission for the cases A, B, and C."

Plank said the latest wastewater sampling results, showing no signs of widespread community transmission, offered a little more reassurance, he added that we still hadn't seen wastewater test results from Papatoetoe High School.