Auckland is at alert level three, and the rest of the country level two, until midnight tonight. At 5.30pm this evening, we’ll find out what happens next. These are the factors cabinet is likely to consider in making the decision.

During the first wave, the announcement we were moving into lockdown felt sudden. This time, it really was. Overnight, we went from level one with zero cases of Covid-19 in the community to four cases and level three in Auckland. Now, the country sits on 17 confirmed cases (but has possibly up to 18, with at least one case reported in Tokoroa today, or 19, depending on whether the child from the Torbay school reported last night was among the number confirmed yesterday or not).

It feels like a massive jump, but compared to what happened in March it could be much more manageable. While public opinion and economic punditry might imply a level four lockdown would be devastating, our government has shown its willingness to go hard and go early on Covid-19 in the community.

Will that happen this evening? These are the factors at play.

Rising cases

Last time the entire country went into level three lockdown, on March 23, the total number of cases was 102, after 32 new cases were confirmed in one day. Right now we have 36 cases in total, 17 of which are classified as community transmission, 13 of which were identified yesterday. At least one new case has been reported in Tokoroa since yesterday’s 1pm announcement, and while they remain unconfirmed by the Ministry of Health minister of health Chris Hipkins has said more cases linked to the new cluster will be announced at today’s 1pm update.

Compared to the last wave, this is about where we were at prior to the alert level system being introduced. By the time alert level three and subsequently alert level four were put in place in March, the number had almost doubled within two days, from 54 cases on March 21.

The source

While the source of the outbreak hasn’t yet been confirmed, all cases appear to be linked to the Americold cluster, which is somewhat reassuring; level three may have been put in place before it could spread further into the community.

Tracing the outbreak to its source is easier under level three conditions, so it’s likely Auckland will remain at a semi-standstill until the index case, or a batch of cold-store virus, is found. Professor Shaun Hendy, director of Te Pūnaha Matatini, told the Science Media Centre he was particularly interested in upstream contact tracing – where contact tracing is used to find the source of infections, rather than the resulting cases. “It is a technique that was used widely in Japan to contain their outbreak,” he said, describing it as “cluster-busting”.

Genomic sequencing is already providing results to this effect. As director general of health Ashley Bloomfield announced yesterday, the genomic sequences most similar to these cases are from the UK and Australia.

The modelling

An R0 number tells us how infectious a virus is: if its R0 number is 1, then someone with the virus will infect, on average, one other person. Covid-19 has an estimated R0 number of 2.2, and that’s a relatively conservative estimate. It’s clear steps must be taken to prevent the spread; it won’t die out naturally.

Mathematical modelling tells us the probability of the spread; where, who, and what the source could be. Modelling will heavily influence the decision made this afternoon. Yesterday, Michael Plank, a member of the modelling team, said the worst-case scenario was a super-spreading event. Last Saturday’s fried chicken festival and Labour Party campaign launch are examples of big events that have the potential to be super-spreaders, but it’s likely there would be an indication of infection from these events by now.

Contact tracing

Downloads of the Covid-19 tracing app have been rapidly rising since Tuesday, when the first cases of community transmission were announced. Nearly one million New Zealanders have now downloaded the NZ Covid Tracer app, according to Bloomfield. He said at yesterday’s press conference that there were “338,200 new downloads of the app, 514,901 QR code scans and 292,502 manual diary entries” since Tuesday night.

Yesterday was the first time an alert had been sent out via the app, to people who were in certain locations that two members of the infected South Auckland family visited during their trip to Rotorua.

In March, Victoria University computer scientist Simon McCallum told Stuff the tracer app would be useful only if one to two million people downloaded it.

The state of testing

Yesterday, Bloomfield said 6,006 tests were processed on August 12, the day after it was announced Covid-19 has re-entered the community. He said that more than 10,000 swabs were collected, leaving just under 4,000 still to be processed from that date; we’ll hear about them today. Testing didn’t slow down on August 13, and there are now 16 community testing stations open in Auckland. There is no shortage of swabs, and GPs have been told they can order as many as are needed.

Tests take around 24 hours to process, so we’re more likely to see a large boost in case numbers today than yesterday.

Testing in Rotorua has also been high over the past two days, and if the virus spread during one case’s weekend visit it’s likely we’ll know by this evening.

Currently, nasal swabs are the only test used. Pool testing – which would enable whole suburbs, streets or even larger communities to be check for presence of Covid-19 – is currently possible but is not being done.

A Ministry of Health spokesperson said not to worry if a test result was taking longer than 24 hours.“If the result is positive, the person will be quickly informed,” they said. “If it is a negative test it may take slightly longer for the person to be informed of the result.”

The spread

A new case of a child who goes to school in Torbay overnight suggests a spread of Covid-19 to the North Shore, which would mean both urbanised ends of Auckland are infected. It’s expected this new case will be connected to the Americold cluster.

Testing has been ramped up in Rotorua and Taupō, with two testing centres in Rotorua and one in Taupō completing a combined 554 tests on Wednesday alone, following information that the South Auckland family had visited last weekend. So far there have been no confirmed cases outside of Auckland.

Today, media are reporting at least one confirmed case has been discovered in Tokoroa, a Waikato town about two and a half hours south of Auckland. It has been suggested the two have links to the Auckland cluster. Yesterday, it was revealed that one of the Americold cluster cases had visited a rest home in another Waikato town, Morrinsville, prior to becoming symptomatic, but Morrinsville and Tokoroa are an hour’s drive apart, and there doesn’t appear to be a link.

The cluster numbers

Currently there is only one cluster, officially confirmed as 17 people, comprising the original four from the South Auckland family and 13 of their contacts. During the peak of New Zealand’s first outbreak there were 16 active clusters.

It’s unknown for certain whether the Tokoroa case and the Torbay student are part of this same cluster, though it’s very likely they are.

The public mood

In May, a Newshub-Reid research poll found 91.6% of New Zealanders supported the lockdown.

While there are still huge amounts of public support for the government’s response to Covid-19, ideas originating from US-based conspiracy groups have made their way here. These ideas question the validity of the public health information that’s been circulated by the government, and include anti-mask and anti-lockdown sentiment, as well as Covid-19 denial.

A protest against a nationwide lockdown was planned for tomorrow in central Auckland, and a small anti-lockdown march has already taken place in Whangārei, which is at level two. National Party deputy Gerry Brownlee has also been accused of inciting further mistrust for sharing doubts about whether the government has shared all necessary information with the public.

Our guess

The immediate rush to get tested means we’ll have a strong indication of how far the virus spread by this evening. “Stop the spread” and “go hard and go early” have been the approaches so far. With a confirmed case allegedly found in Tokoroa, a regionalised shift to level three centred around that town is possible. It’s also possible the entire country will shift to level three, or that just the North Island will level up.

Health minister Chris Hipkins said this morning that for New Zealand to move to alert level four there would need to be “a number” of clusters and unconnected cases. While “one” is a number, it probably won’t be high enough.

During the last lockdown, we were told two weeks were needed for the virus’s lifecycle to complete. It’s likely that even if case numbers don’t significantly increase, at least Auckland will will remain in level three for two weeks from August 11. If a significant number of cases is found in Auckland, it could move up to level four.