Whether or not Auckland is dealing with a bigger Covid-19 cluster will not be known until the next day or two, with a group of gymgoers being tested for the virus for the first time tomorrow.
People who were at City Fitness Papatoetoe at the same time as a young man, who later tested positive for Covid, are considered to be casual plus contacts.
The last time the 21-year-old was at the gym, inside Hunters Plaza, was on Friday (February 26) between 3.25pm and 4.30pm.
As casual plus contacts, they need to have a test on or after day five from the date that they were last exposed to the case, the Ministry of Health says.
The official definition of a casual plus contact is someone who has been exposed to a case where there may be a higher risk of transmission - but who does not meet the criteria of a close contact.
Officials have updated information for those who were at the gym at the same time as the infected man via its locations of interest page, on the Ministry of Health's website.
"Please stay home, get a test on the 3rd of March. If you were at the gym during this time and have not been contacted then please phone Healthline for advice on 0800 358 5453."
People are reminded to stay home until a negative test result is received.
But if symptoms develop after a first negative result, get another test done immediately and stay home until a negative result is received, the advice reads.
Why the delay to be tested?
Otago University infectious diseases expert Professor David Murdoch said the move to wait a few days after people had been exposed to an infected case was most likely to ensure that the best quality information was picked up when tested.
"After exposure, there is a general concern if you test it too soon, you might miss it.
"You could test them immediately... but the best bang for your buck is to test them later."
He said any exposure in an enclosed area, where people were in close proximity to each other, presented a risk of infection.
The fact that this happened at a gym, where people shared exercise equipment, was also a key factor.
The chance of other community cases arising from the gym were therefore "reasonably high" still, he said.
University of Canterbury epidemiologist, Associate Professor Arindam Basu, said testing someone around the fifth or sixth day after being exposed to an infected case was the best time to test as the virus would be at its peak.
Basu said if the infected case had used shared exercise equipment, even if he had wiped down the machines with sanitiser, there was still a high risk of someone else catching the virus through droplets in the air.
Depending on the air circulation in the gym and whether there were any windows open, for example, the droplets could move from one side of the room to another part of the room.
"What was the flow of the air around him and (how close) were the people on the other machines near him?"
Basu said: "If we're extremely lucky, we may have no cases."
The young man who visited City Fitness Papatoetoe was also at that gym on Saturday, February 20.
Anyone who was there between 11.15am and 1.45pm on that day is also regarded as a casual plus contact.
Like those who were at the gym on Friday, they are advised to stay home and get tested for Covid as soon as possible.
Anyone who was at the gym at the same time but has not been contacted by health authorities is asked to call Healthline for advice.
People who were also in the vicinity of the gym, inside Hunters Plaza - between 11am and 2pm, on February 20, and between 3pm to 5pm, on February 26 - is a casual contact who should still keep an eye on their health in case any flu-like symptoms develop.
Casual contacts are advised to monitor their health for 14 days and to call Healthline if they start to feel unwell or develop any Covid symptoms during that period.
Murdoch said whether or not alert levels would drop by the weekend would depend on the results seen over the next few days.
"The decision about lockdown is all around getting the confidence that it's been contained. Is everything connected? Have we got everything contained?"
Symptoms for the virus are similar to the common cold or flu - which is why people are told not to go into work or school if they become sick.
Covid symptoms include a new or worsening cough, a fever of at least 38C, shortness of breath, a sore throat, sneezing and runny nose or a temporary loss of smell.
People affected in the February cluster have also reported feeling fatigued and having muscle aches.