After resorting to knocking on doors, contact tracers last night had just one Papatoetoe High School student left to track down and test for Covid-19.
The 10-day delay to reach the final handful of students has been labelled "frustrating" by Covid-19 Minister Chris Hipkins.
Health authorities are now regarding hundreds of customers at two East Auckland stores where a Covid-positive teenager worked and shopped as close contacts in their updated locations of interest schedule.
There are now fresh instructions on what staff, customers and those living in the same households should do if they have been in either the Kmart or vape store at the same time as an infected teenager.
It includes a mandatory spell of quarantine and testing for staff and customers of Kmart Botany and Dark Vapes, with those who share a home with staff to stay put until the affected worker gets back a negative result from the first test.
Contact tracers last week called the students, their families and sent texts and emails in attempts to get hold of everyone and ensure they had tests following the Valentine's Day outbreak at the school.
By the end of the week, more than 98 per cent of Papatoetoe High School's students and staff had been contacted and tested.
However, authorities struggled to track down a small number and took to door-knocking on Monday. By last night it was understood to be down to just one student who hadn't been tested.
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One of the students who couldn't be reached went on to test positive on Tuesday. Later that day two of the student's siblings also tested positive.
One of those new cases, a teenage girl, worked two shifts at Kmart Botany, folding clothes, greeting people at the entry and manning the click-and-collect counter in the evenings on February 19 and 20.
The store's 300 staff are deemed newly created "casual plus contacts" and have been told to isolate and get tested while the 870 shoppers identified as being there during the teen's shifts are "close contacts".
They have also been told to stay home for the full 14 days and get two tests out of the need to be "especially cautious".
These tests are to take place today and again on March 4.
A new advisory has been issued for people who share a house with Kmart Botany and Dark Vapes customers and staff.
If you share a house with a staff member health authorities are advising everyone to stay in their homes until the employee returns a negative day five test result.
If you share a house with a customer the advice is only to stay at home if the customer has symptoms.
No new community cases were added to the 11-strong Valentine's Day cluster yesterday.
Director general of health Dr Ashley Bloomfield said one of the reasons some of the students didn't get tested earlier could have been that they faced barriers like relying on a family member to get to a testing centre.
Auckland Regional Public Health Service said in the event someone couldn't be contacted other factors - like not having an active phone, not speaking English or personal circumstances - could be at play.
Bloomfield said the key thing was ensuring the students were isolating because they couldn't return to school without a negative result.
"You can't rely on luck with this virus. That's why we had the protocol in about not returning to school unless they have a negative test and that transpired to be exactly the right thing to have done."
Top epidemiologist Michael Baker says being able to contact and test 98 per cent of the school's 1500 students and 150 staff within a week was an example of the system "working well".
"It could be problematic it took time to reach those last students ... but it's harsh to say [the contact tracing system] performed poorly given the circumstances," said the University of Otago professor.
Baker said "most of the time" contacting most of a casual contacts was "good enough" but every close contact definitely needed to be contact.
His overall impression of the Papatoetoe High School outbreak was the contact tracing system performing well, especially given the vast number of casual and casual plus contacts they needed to reach.
The responsibility fell on the Auckland Regional Public Health Service but resources were brought in from the National Contact Tracing system to help.
The "gold standard" of contact tracing identified in Dr Ayesha Verrall's report last year is finding 80 per cent of a case's contacts within three days.
Hipkins said they were relying on people "doing the right thing" when asked how they were ensuring compliance outside of the daily phone call symptom check.
"You're being asked to isolate for a reason and we need people to follow the rules."
He has not received advice on whether other measures are needed to ensure people are following the order.
Everyone told to isolate but who can't work from home is eligible for the $585.50 Covid-19 Leave Support Scheme wage top-up.
With so many people being ordered to stay home the Government said it was "watching the situation closely" as to whether they needed to expand support.
"Each individual case will be different and some people may need more support than others," said Social Development Minister Carmel Sepuloni.
Everyone at Papatoetoe High will now need a second negative test before going back to school. More than 600 students and staff were tested on Monday and a further 328 had been swabbed by 1pm yesterday.
Remote learning was being offered to students who were missing their second week of classes.
Genomic sequencing confirmed the latest cases were connected to the three reported on Valentine's Day.
But how the latest schoolgirl was infected is an enigma - she barely knows the other students and isn't in their classes.
One of the lines of investigation is whether she caught the virus through airborne particles in a hallway or bathroom.
Bloomfield said it was a curious nature of the new UK variant that most of the cases' close contacts hadn't been infected but others with just fleeting interactions had been.
The new strain also appears to present with different symptoms - such as muscle aches, lethargy and a loss of smell - rather than those similar to a cold like earlier variants.
He urged Kiwis not to dismiss painful muscles and confuse the symptom with soreness after exercise.
Both Hipkins and Bloomfield said they were still confident with having Auckland at alert level 1 but if more cases cropped up without a clear path of transmission, that could predicate a change.
"[The] news of additional cases I know was unsettling and feels like another climb up on our rollercoaster ride. But it does not need to be alarming. I'm confident the system is working as it should."
Meanwhile the 1000th Kiwi got their vaccination yesterday as the roll-out continues through border workers at managed isolation facilities.
When the wider vaccination campaign is set to reach the general population, Bloomfield said he would be among the community leaders to publicly get the jab.