Cabinet will have to weigh up test results, cases among essential workers and the virulence of the Delta variant in making an alert level decision today, Marc Daalder reports
Cabinet will meet today to decide what happens to the alert levels outside of Auckland.
While some in Wellington and other parts of the North Island may feel resigned to at least a few more days at Level 4, the South Island will be hoping for a call to move to Level 3.
The central consideration for Cabinet will be how certain it is that there are no cases in any place set to move down. It will face challenges in making that determination, however, due to slow contact tracing which has clouded the Government's visibility of the full potential extent of the outbreak.
There's a slight perception problem for the Government if it decides to move part of the country down to Level 3, in that cases are still rising. But this is less important from an epidemiological standpoint than the source of new cases.
Level 3 no match for Delta
The last time we moved out of Level 4, the Government was confident it could handle small numbers of cases at Level 3. Likewise, the two previous Auckland outbreaks were dealt with at Level 3 with little thought of needing greater restrictions.
Delta changes this calculus. While the original virus was reliant on super-spreading events to spark an outbreak from a single case, Delta doesn't have the same weakness.
At Level 3, bubbles are allowed to combine and most workplaces can operate, with certain restrictions. Mass gatherings are limited, with narrow exceptions for funerals and tangihanga.
A single case of Delta could swell into a firestorm at Level 3. It could transmit from bubble to bubble and through workplaces. And, as we've seen with this outbreak, it only takes a few days for one case to turn into 277. Even if we're quick to catch a resurgent outbreak at Level 3, it would require a return to Level 4 to stamp out.
Given this, Cabinet will have to be satisfied that there are no active cases outside of quarantine in any location it moves down to Level 3.
On at least one front, there are positive signs for everywhere other than Auckland and Wellington. Since the start of the outbreak, more than a quarter of a million Covid-19 tests have been taken - representing 5 percent of the population.
In every District Health Board other than South Canterbury, more than 1 percent of the population had a test in the first week of the outbreak.
That's the threshold that Director-General of Health Ashley Bloomfield said was needed for surveillance testing to have the best shot of turning up undetected cases.
Theoretically, that should rule out cases in any place where no positive results have come back.
The long tail
There's a complicating factor here, however: The so-called long tail of Covid-19. With the original virus, some people only developed symptoms two weeks after they were infected. While most people with Delta become symptomatic in the first week after they're infected, it's unclear whether the 14-day rule still applies in some rare circumstances.
That raises the risk that people who visited a location of interest in the handful of days before lockdown could still be incubating the virus. They may have tested negative once, but could still develop symptoms and become infectious over the weekend or earlier next week.
In the past, Cabinet took a precautionary approach and made decisions based on these 14-day transmission cycles. Given the extreme care with which the Government has treated this Delta outbreak - moving to Level 4 when there was only one known case - it's hard to imagine them discarding the 14-day rule entirely.
Covid-19 can also be asymptomatic, meaning some carriers who are infectious wouldn't be tested unless they were at a location of interest or are otherwise a contact of another case. Here's where the Government's contact tracing woes come into play.
As of Thursday afternoon, 24,402 contacts had been identified but more than a third of these had yet to receive a call from contact tracers or an instruction to isolate. That means they could still be visiting essential businesses - or even going to work, if they're essential workers. More than a quarter of the contacts have yet to be tested, Director of Public Health Caroline McElnay said.
Is lockdown working?
The other consideration for Cabinet, beyond the potential long tail of pre-lockdown transmission, is whether there has been transmission during Level 4.
At least a few essential workers have tested positive for the virus, Prime Minister Jacinda Ardern told Newsroom on Thursday. Those included a handful of nurses, an MIQ worker, people who work in non-customer facing roles in food production and a Countdown employee in Auckland.
Essential workplaces are one of the few places that could allow Covid-19 to spread outside of and between bubbles at Level 4. They are the necessary "weak spot" in our strict arrangement, and must be treated with the utmost caution.
While Director of Public Health Caroline McElnay emphasised that the food production workers would have been operating under stringent distancing and PPE conditions and were therefore unlikely to spread the virus to one another, the Countdown employee worked two shifts while potentially infectious, according to the locations of interest register.
Alongside essential workers, unlinked cases raise concerns that the virus may be escaping bubbles and moving through the community. Ardern indicated that 16 of the 62 cases reported on Wednesday were still unlinked, but said it wasn't unusual for investigations to take time to find a link.
Over the first few days of the outbreak, the Government reported the cumulative number of linked and unlinked cases each day. They stopped doing so on Wednesday.
The Ministry of Health was unable to provide the latest information on Thursday.
If there are unlinked cases spanning back to the weekend, that could indicate that investigations have failed to find an epidemiological connection to a location of interest or other Covid-19 case. Presumably the Government has that information to hand, even if they aren't releasing it.
Ardern at least seems confident that Level 4 has held up so far.
"Every time we’ve asked the [Auckland] public health unit whether or not they have a concern that there are compliance issues or anything to demonstrate Level 4 is not working, the answer I’ve gotten back has been no," she told Newsroom.
The ultimate question, therefore, will be whether that confidence outweighs the risk averseness with which the Government has approached Delta over the course of the outbreak.
