'Too little, too late': Allegations Covid-19 testing regime unprepared for Omicron, still weak on much-needed saliva tests
Thursday, 20 January 2022
A Covid-19 saliva testing expert from Yale University is “terrified” at how unprepared the Government is for Omicron, and says it urgently needs to ramp up saliva testing of border workers before it is too late.
Yale University’s Anne Wyllie says New Zealand authorities need to test border workers daily, and pay attention to new research showing saliva testing is better at detecting Omicron.
“I’m terrified it’s going to be too little too late. New Zealand has had almost two years to straighten out its testing system, to get things in place.”
Wyllie, a Kiwi expat, has been dubbed “the spit queen” for her important research on saliva testing, and is part of a group advising United States President Joe Biden on Covid-19 testing.
**READ MORE:
* Saliva testing saga continues with 'frustrating' and 'short-sighted' U-turn on MIQ returnees
* Iwi's 'yaks and vax' mobile clinic proves a great success
* Covid-19: U-turn on saliva testing as fears grow around nasal swab hesitancy
**
A study from the University of Cape Town, in South Africa, finds nasal swabs, which performed well with the Delta variant, were less effective at detecting Omicron. It concludes nasal samples may be “suboptimal” for detecting the new variant.
Even if you are sticking with nasal polymerase chain reaction (PCR) tests, Wyllie warns testing high-risk border workers once or twice a week is nowhere near enough to get on top of an Omicron outbreak.
A Ministry of Health spokesman says they are continually reviewing testing requirements, but testing frequency for MIQ workers needs to be “proportionate to risk”.
Wyllie says New Zealand needs to be aiming to process 100,000 Covid-19 tests a day, a throughput well above the peak of nearly 50,000 tests recorded on one day in August.
Opposition parties National, ACT and Te Pāti Māori have similar concerns around the number of times MIQ workers are being tested, along with poor turnaround times at labs, and slow moves to provide a greater variety of Covid-19 tests to the general population.
Te Pāti Māori co-leader Debbie Ngarewa-Packer labels the hold-up on a wider roll-out of saliva testing as “bizarre”.
Last year, during the Delta outbreak, iwi in Taranaki largely gave up on the public Covid-19 testing system, instead training up their own volunteers to administer saliva tests from Rako Science.
She says the availability of saliva testing made a real difference to how willing people were to be tested.
The Ministry of Health would not subsidise these saliva tests, part of a long-running feud between Rako Science and the Ministry of Health, so Taranaki District Health Board paid for them instead.
Ngarewa-Packer credits saliva testing with helping contain an outbreak in Taranaki over the summer period, while much of the public system was closed.
“In Hāwera, for example, we had an instance where the testing station closed down, even though it had queues, because it was closing time,
“I know that the Government’s congratulating itself … [but] this success has happened over summer because we’ve had Māori and iwi volunteers and health providers who have been working consistently, they haven’t stopped.”
An outbreak at Eltham school on December 15 was quickly contained after 11 students were shown to be Covid-19 positive within a day of saliva testing being rolled out at the school by volunteers from Ngāti Ruanui and Ngāruahine.
Ngarewa-Packer says MIQ workers are being tested less frequently than community volunteers in Taranaki who are sometimes being saliva tested twice a day: when they start work, and when they clock-off.
She says workers tested in the morning would often receive their test results by the afternoon.
“We all know that Omicron is going to break through, it’s going to get into the community, we may have a week or two up our sleeves,'
“A lot of those coming home are Kiwis, they need to come home, but I think what we should be doing is [stopping] making testing so hard to access.
“You’ve got to have the saliva testing, which, again, is more efficient … the best that we can do is test, and test, and test every gap, and every movement, so that at least when it gets out we’ve got some containment.”
National Party Covid-19 spokesman Chris Bishop says the Ministry of Health needs to look at testing MIQ workers more frequently in light of Omicron.
He also sees a chance to run saliva testing alongside nasal swabbing and rapid anti-gen testing for returnees, similar to a trial the Government planned to do but abandoned late last year.
“You’ve got a real opportunity to get some great data, which can then inform policy decisions, so why wouldn’t we be doing saliva testing, but also using rapid tests in MIQ?'
ACT leader David Seymour is also in favour of testing MIQ workers more frequently, as Omicron seems to “slip in between tests”.
He sees this as a better way of preventing an Omicron outbreak than turning the tap off on returnees.
“Testing MIQ workers more frequently is probably going to be more likely to stop an escape, considering there’s a whole lot of people with Omicron in MIQ now.
“Why don’t we improve the quality of the testing regime which could easily be done even with contracts they already have with Asia Pacific Healthcare Group (APHG).
Over the weekend the Ministry of Health revealed a worker in managed isolation had tested positive for the Omicron virus with a nasopharyngeal swab test, but that it had taken two days for their test result to come through.
In that time the border worker had visited a popular central city supermarket, a butchery, and taken several buses, all while unaware she had the virus.
A ministry spokesman says the detection of an Omicron case at the border is evidence the current system works.
In defending lab turnaround times he makes the point that, in recent times, 94 per cent of Covid-19 test results have been processed within 24 hours of being received at a lab.
However, others, like Wyllie, say this is not the right metric to use.
They argue we should be looking at how long it takes from when someone gets tested, to when they get their result, which includes the time it takes to transport a sample to the lab. It is the measure used by Ayesha Verrall during her audit of Covid-19 testing in April 2020.
Wyllie says total test turnaround time is the more relevant statistic because it looks at the total time someone might be infectious in the community after they are tested.
She is an advocate for saliva testing for Covid-19, which can be administered more often than a long nasal swab, because it is less invasive.
Samples from this form of testing can be self-collected, you just need to drool into a tube, and results come within a few hours. This means fewer medical staff are needed, and tests are cheaper to administer. It is also more accurate than rapid antigen testing, where results are delivered within half an hour.
Recently, saliva testing has taken on renewed significance in light of Omicron, with fewer symptoms of the new variant associated with the nasal cavity.
Health authorities around the world are scrambling to integrate the use of saliva samples into their rapid tests, some of which were not designed for saliva testing.
Reuters reports Israel’s Health Ministry is advising its people to run both throat and nasal samples through antigen tests, something not recommended by the manufacturers or the US Food and Drug Administration.
Antigen testing can use either nasal or saliva samples, but some governments, like New Zealand’s, have only bought and authorised the use of nasal rapid antigen tests.
The New York Times also recently covered the changing profile of Omicron and how research showed it was showing up earlier in saliva.
Wyllie says the South African study has not been peer-reviewed, and has a small sample size. However, she also notes South African researchers have often struggled with saliva testing. So the fact they are detecting real differences now, is a noteworthy sign.
There were signs saliva PCR testing is better for early detection of Covid-19 even before the Omicron variant reared its head. The University of Illinois used saliva testing to get cases on its 48,000-strong campus down to zero, and a California Institute of Technology study found saliva tests detected Covid-19 in unvaccinated people more than four days before some nasal tests did.
New Zealand has saliva PCR testing, but its roll-out has been mired in bureaucratic wrangling, contradictions, and concerns about the lab practices behind the validation data used for the Government’s preferred saliva test, which is delivered by Asia Pacific Healthcare Group.
Saliva PCR testing was recommended by the Simpson Roche report in 2020, and the Ministry of Health later procured a border worker contract with the ambition of creating a system that could process up to 20,000 saliva tests a week.
The saliva testing system that came out of the other side of that procurement process took months longer than initially promised to set up, and fell short, in terms of the number of tests conducted.
The auditor-general eventually lashed the ministry for the way it conducted its procurement process, including for the conflicts of interest involved.
As the saliva testing debate has dragged on the Ministry of Health and other bodies, like the NZ Microbiology Network, who expressed accuracy concerns, have been forced to reverse those positions in light of scientific evidence.
Wyllie says there is no time to lose in shoring up our systems. She is seeing the havoc of Omicron firsthand, as Yale’s SalivaDirect Covid-19 test is being rolled out in US schools.
“There have never been such high case counts in schools around students, staff.
“We did a pop-up community testing site the other day … 99 [people] showed up, 36 tested positive.”