It was a night of celebration and mingling that attendees would later describe as “motivating”, “inspirational” and an opportunity for “great networking”.

Ironically, it was the same night that plunged scores of New Zealanders into two weeks of self-isolation after someone who attended the event tested positive for the Delta variant of Covid-19.

“I was not really worried when I first found out, but then all the ramifications of being there sort of hit home,” said John (not his real name).

He was one of hundreds of people from all over the country who attended the Bayleys Real Estate national conference at the Spark Arena in Auckland on August 13.

After the positive case came to light, the conference was on Friday identified as a location of interest related to the current Covid-19 outbreak, and all attendees were told to self-isolate and get tested.

John said when he and his colleagues learned this, some were more anxious than others. But everyone knew it was important to follow the proper health protocols.

“We had people at that conference from Christchurch, Wānaka, Ashburton, Nelson, Blenheim, Invercargill – just all over the South Island.

“And because no-one knew, everyone moved around as normal until the Tuesday [after the conference] when the country went into lockdown. It’s nobody’s fault, no-one knew, but that is how the gate gets left open.”

By Monday at least 120 people who were at Auckland hot spots were self-isolating in the South Island, the Ministry of Health said.

All were instructed to get tested, and to date no positive cases have popped up.

But a decision to move the South Island out of lockdown is not as simple as having no positive cases of Covid-19, says leading public health professor Nick Wilson.

“We cannot be absolutely sure unless a longer period of time has elapsed and more testing has been done.

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“At the moment there are over 100 close contacts in the South Island, and you just need one infected person to not follow the rules and start off another chain of infection, especially if they get into contact with essential workers.”

This is compounded by the fact New Zealand is now battling the Delta variant, which is at least twice as transmissible as the original Wuhan strain of Covid-19.

 

There is also evidence Delta has a much shorter serial interval, the time it takes between someone becoming infected and infecting others.

On Tuesday, Director-General of Public Health Dr Ashley Bloomfield said dealing with the Delta variant was like dealing with “a whole new virus”.

Easing restrictions

On Monday, numerous experts applauded the Government’s decision to keep the whole country in alert level 4 until Friday, even though the South Island remained without a positive case.

Professor Michael Plank, of the University of Canterbury’s School of Mathematics and Statistics and principal investigator at Te Pūnaha Matatini, said extending level 4 was “the right decision” while the true extent of the outbreak was still uncertain.

“By Friday we will know more and a drop to alert level 3 is a realistic possibility for regions with no active cases,” he said.

But Queenstown Lakes District Mayor Jim Boult​ said he could not see the point of the South Island moving into alert level 3 and it should move directly to alert level 2.

“If we’ve got no cases in the South Island come the end of the week, and we’re pretty much past the incubation period, then it’s time to get a bit of normality back.”

While level 3 offers not much more than the ability to buy coffee, level 2 means most businesses and schools can operate.

Under alert level 2 ski fields would be able to open, encouraging visitors to Queenstown and Wānaka who would bolster the local economy.

“What worries me is that if this goes on for a long time then we risk the fact that the ski fields might say, ‘We can’t hold on any longer’, and it might be difficult to get them going again.”

Tourist towns are not the only ones struggling under lockdown.

New Zealand Principals' Federation national president Perry Rush said the hybrid model of providing education under alert level 3 was difficult for schools.

They are required to be open for children whose parents or carers need to go to work, not only those classified as essential workers. However, they must provide distance learning options for all children who are learning from home.

Schools were surprised at the low numbers of children who attended during level 3 in 2020 – only one or two per cent of the school population.

“It will be interesting this time to see if there’s any more confidence around attending school,” Rush said.

Even if no cases of Covid-19 are identified in the South Island by the weekend, Wilson said he would expect the South Island to be moved to level 3 first before level 2 could be considered.

“We need to be absolutely sure,” he said.

John received his first Covid test at a local medical centre on Saturday, and his day 12 test will be done on Wednesday.

A second test around day 12 is important because of the period of time it can take for some people to incubate the virus and test positive.

Plank said relaxing the alert level too early while cases are still in the incubation period could lead to “a disastrous outbreak, especially given how quickly the Delta variant can spread”.

Many of the attendees at the Mitre 10 Awards Dinner that took place on August 12 in Auckland, which has also been identified as a location of interest, received their day 12 tests on Tuesday and are awaiting the results. Host Hilary Barry is among those who are isolating after the event.

North and South

Wilson said it was vital for the Government to put the necessary precautions in place to prevent the virus from crossing if the North and South islands were potentially to operate at different alert levels.

For example, trucks from the North Island could be driven onto a ferry and picked up by South Island truck drivers on the other side to prevent essential workers from moving back and forth.

On whether testing of a certain percentage of the population could provide assurance of a region being Covid-free, Wilson said that would need to be calculated by taking into account the impact of wastewater testing as well.

“Wastewater testing can be very accurate and very sensitive. No-one has yet calculated the combined value of wastewater testing with the value of the individual Covid tests being done.”

He said it was difficult to predict what the impact on the Covid response would be should a positive case emerge in the South Island within the next few days.

“It would all depend on the context. Everyone is in lockdown, so a positive case could only infect the people in their household and then the virus would have nowhere to go.

“But if a case turned up in an essential worker, that would be more serious depending on the amount of contact the worker had with other people,” he said.

He said one positive case in the South Island would not necessarily be indicative of more positive cases lurking in the region, since all the Covid testing and wastewater testing has been negative to date.

Testing ramped up

Brent Gilpin, senior science leader at the Crown’s ESR research facility, said the institute has significantly increased its testing over the past week since the outbreak.

Last week wastewater samples were taken at Christchurch, Nelson, Westport, Dunedin, Queenstown, Invercargill and Gore.

This week Picton, Blenheim, Reefton, Greymouth, Methven, Ashburton, Rakaia, Amberley, Hanmer Springs, Kaikoura, Leeston, Rolleston, Rangiora, Kaiapoi, Timaru, Oamaru, Alexandra, Cromwell, Mosgel, Wanaka and Bluff will be added to the schedule.

“Wastewater samples were taken weekly or in some cases twice weekly from our 26 sites prior to ESR's increased testing following the identification of the virus last week,” said Gilpin.

“From August 11 up until August 22 there were 14 wastewater samples tested by ESR. In all cases the virus was not detected.”

He said no decision has yet been made on future requirements for wastewater testing, or the possibility of expanding the programme beyond the 26 sites announced last week.

According to the Ministry of Health, 35,376 Covid-19 tests were processed across New Zealand on Monday.

A ministry spokesperson said between August 17 and August 23, 24,681 tests were processed and reported by laboratories for the South Island.

“The greater transmissibility of the Delta variant means that the virus spreads faster. For this reason, we need to maintain a high level of daily testing to have confidence in our assessment of the outbreak.”

Officials are expecting cases to continue to increase in the next couple of days, but for the spread of the outbreak to slow down later in the week.

“Testing as many symptomatic individuals and potential contacts as possible remains a priority in our assessment of spread and in determining the edges of the outbreak.”