Health officials planned to take wastewater samples from the portaloos at the Parliament protests to test for Covid-19 but then decided against it, internal email chains have revealed.
Following unsuccessful attempts to retrieve suitable samples over the second weekend of the protest, the Ministry of Health decided further testing was unnecessary from a public health perspective and could even undermine negotiation efforts.
The Ministry of Health revealed last week a total of 26 cases had been linked to the protest - fewer than the earlier figure of 28, as authorities said there had been duplicate reports.
Emails revealed to the Herald under the Official Information Act show that officials planned to collect "portaloo effluent" from the protest site on the weekend of February 19 and 20.
A senior scientist gave instructions on February 16 for how to collect the samples – three samples taken each day, over the two days.
The email referenced that the scientists had sent sample bottles, chilly bins and chilly packs, and advised the collector to keep the samples cool until they could be picked up.
However an email dated Monday Feb 21 said the sampling never took place.
"The large increase in people at the protest over the weekend led to extra rubbish being disposed of in the portable toilets," said Public Health Medical Officer of Health Dr Stephen Palmer.
"This hampered the ability of the provider to empty the portable toilets and obtain a sample after servicing the toilets at Parliament."
Sampling was also hindered on the Monday due to "happenings at the site led by the police", he said.
A Ministry of Health spokesperson confirmed public health officials were unable to obtain samples and testing was never undertaken.
Emails the following week reveal the Ministry decided against attempting further testing, which they said was a request that initially came from NZ Police.
An email from Covid-19 Health System Response Directorate Brent Quin said he believed the testing was neither in the public health interest nor the wider interest.
"Firstly, everyone at the protest should be treated as a case," read the email.
"Additionally, positive waste water sampling in what is a transient protest group (people come and go) remains of little value, and should positive results be returned, the question becomes what could possibly be done with that information?"
He said there would be a duty of care for health officials to then undertake Covid testing in that environment, which would be "the next obvious action" following positive wastewater results.
"If individuals then return a positive test, again we must ask what authorities would do with that information?"
He expressed scepticism that any positive cases from the protest group would provide personal details and voluntarily self-isolate, nor accept being placed in accommodation.
"From a public interest perspective, we believe such testing would create greater friction and potentially undermine any negotiations and/or unintentionally place public health as the rationale should there be a later decision to clear the protest site."
"Any perception to this end would significantly undermine further public health responses."
An earlier email from public health operations group manager Toby Regan said the wastewater sampling was of little public health value "given that we know we have widespread infections across the Wellington area."
"A positive result only confirms that people who used those facilities (which are open to the general public) have had Covid in the last few months, likewise a negative result says that no one was excreting Covid at that time."
"Neither outcome adds to the public health picture in my opinion."
A Ministry of Health spokesperson confirmed it was deemed unnecessary to take further samples after the weekend of February 19 and 20.
"Wastewater detections can lead to increased local vigilance and clinical testing as well as allow health authorities to target public health advice to prevent transmission," they said.
"The frequency of sampling varies depending on the local population, access to wastewater collection points and risk factors."
"In this instance, it was deemed there was no need to take repeat surveillance samples from the protest site, as positive test results were subsequently confirmed among the group of protesters in the following days.
"The Ministry advised all those at the protest, or who had been at the protest, who are displaying cold and flu-like symptoms to get a test and isolate until they receive their result."
Health authorities also considered making RATs available at the site, in an email dated February 24, following news confirmed cases had been at the protest.
To this suggestion, Police responded that protesters wishing to get a test should be directed to the Taranaki Street testing facility, as they believed setting up a testing station onsite "would only encourage and empower protest action."
The Ministry of Health revealed a total of 26 positive Covid cases had been connected to the Parliament protest.
A figure of 28 had previously been reported by the Ministry, but has been revised due to duplicate reports.
The majority of this number – 14 people – were under the age of 30, while two of the cases were children aged 10 or under.
There were no known cases of Covid-19 that required hospitalisation, although the Ministry confirmed there were two instances of people who had attended the protests presenting to emergency departments.
The first was on February 22 to Wellington Hospital emergency department, while the second on February 24 was to an unknown location.
The Ministry stressed that Covid cases reported from the protest were likely an underestimation.
"During this phase of the Omicron response, case investigations were primarily completed using the self-administered online self-investigation tools, this tool only identifies very high-risk exposure events."
"This protest is not part of this group of exposure events."
"Any links between people who had been protesting at Parliament during this time and subsequently diagnosed with Covid-19 would only have been discovered if this information had been proactively reported to public health investigators."