Covid-19: Call for clarity around rapid antigen testing strategy
Friday, 21 January 2022
Asia Pacific Healthcare Group chief executive Anoop Singh has access to all forms of testing for his staff: the traditional nasopharyngeal swabs, saliva polymerase chain reaction (PCR) testing, and rapid antigen testing.
So what will he use for these critical lab staff, who process a large chunk of the country’s nasopharyngeal Covid-19 tests, when Omicron hits?
“The [Ministry of Health] actually made available lines of these rapid antigen tests to us, which we’ll be calling upon. It really depends on availability.
'Certainly in Australia the key issue’s been availability, but once they’re available they’re quite an effective way of triaging.
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“There’s an order link through the website, and we’ve placed the order … the stock’s available, but we haven’t physically received them just yet.”
Rapid antigen tests are how Asia Pacific Healthcare Group (APHG) is planning to triage symptomatic lab staff, but it has also been using saliva PCR testing as a form of surveillance testing on them from day to day.
“We’ve been actually testing our staff using saliva samples in Auckland for the last two months.
“So we set up our internal surveillance system. Outside of rapid antigen we have that option as well.”
Confusion over rapid antigen tests, along with calls for more of them, have increased over the summer.
Especially with the public nervously eyeing headlines across the Tasman about low stocks and overwhelmed testing systems.
Rapid antigen tests can be administered at pharmacies, do not require labs, and deliver test results in less than 30 minutes.
Adding to the confusion has been the way in which rapid antigen tests have been authorised for use at pharmacies.
The test was restricted to unvaccinated people, without Covid-19 symptoms, seeking to leave Auckland or board a flight.
Yale University research scientist Anne Wyllie says those instructions are “horrendously wrong and dangerous”.
The Carestart antigen instructions, for example, say its test should only be used on people in the five days after a person starts showing symptoms.
If it is not going to be used on the symptomatic, it advises running two tests over three days with only a 24-hour gap between tests.
Wyllie says using rapid antigen tests when people don’t have symptoms is almost wasteful, since there is little chance these tests will even detect the disease that early in their infection, especially if they have Omicron.
“The reason the FDA (United States Food and Drug Administration), everyone else, has labelled them seven days from symptom onset is because that’s when your viral load is the highest.
“In theory if you’re asymptomatic, or pre-symptomatic, you’re not going to pick it up anyway with a [rapid antigen test] so it’s just a waste, that’s when you need a PCR test.
“I just don’t understand how they keep saying that they’ve done their research or consulted individuals because everything they recommend is just backwards and wrong,” Wyllie says.
Employers and Manufacturers Association chief executive Brett O’Riley is one of those in the business community who has been left puzzled for months about what the Government’s approach to rapid antigen testing will be.
“It’s nonsensical and not coherent, I mean we’ve been asking ‘what is the approach?’.”
Access to rapid antigen tests have been tightly controlled by the Ministry of Health, with only a small set of nasal rapid tests approved for use or import.
So when O’Riley filled out the form to import them he was expecting a grilling, or a long lecture with a series of instructions on how they should be used.
His idea was the EMA could distribute tests, and educate other businesses on how they should be used.
But he did not receive so much as a follow-up phone call.
“Finally, two months later, we just get this letter saying ‘by the way you have been accepted to buy and distribute rapid antigen tests', and here’s the name of the suppliers that have got the test in New Zealand, please contact them.
'I mean I could have just done that anyway, I knew who the companies were [with approved tests].'
For some, the Government’s announcement on Thursday was a sign of relief on this front.
It confirmed rapid antigen testing would be part of our future approach to Covid-19 testing, and that these tests (along with more traditional PCR tests), would be free.
However, it also added some more confusion into the debate. Prime Minister Jacinda Ardern appeared to say the focus of laboratory PCR testing resources would shift to the symptomatic.
“Currently we use PCR testing as our primary way of identifying cases,” Ardern said at a press conference on Thursday.
“With wider spread, this system will need to change though. Here, Cabinet has already established several principles for testing into the future, they’ll be focused on people who are symptomatic, vulnerable, essential workers, and close contacts, they will be free.”
Wyllie argues things should be the other way around, PCR testing should focus on the asymptomatic, and antigen tests on the symptomatic.
In other words, use rapid antigen tests for people who have symptoms so that they can confirm they are in the middle of a Covid-19 infection without clogging up the public labs and testing sites.
PCR can better detect smaller quantities of the virus, while rapid antigen tests are better at detecting the virus when it is there in large quantities.
A Ministry of Health spokesman did not know what the policy around lab testing and antigen testing would be, and could not clarify what the prime minister meant by her comments.
“The Ministry of Health is working on a national testing framework and operating model in preparation for Omicron entering the community, as we have seen happen in many other countries,” the spokesman said in a statement.
'This work, including the use, distribution and recording of RATs will be released in the near future.'
Wyllie has conducted research (which has not been peer-reviewed) showing signs saliva PCR tests detect Omicron three days before rapid antigen tests detect it.
Other research has also found Omicron showing up earlier in saliva than in nasal samples.
Israel’s Health Ministry, and others, are advising people to use nose and throat swabs on antigen tests, even if those tests are only supposed to be used with nasal samples.
National Party Covid-19 response spokesman Chris Bishop says overseas experience shows we need a lot of antigen tests available cheaply or freely, followed by very clear guidelines and protocols for their use.
“I don’t have a particular fixed view on what those protocols are, I just want them to exist.”
Te Pāti Māori co-leader Debbie Ngarewa-Packer also warns the Ministry of Health needs to do a much better job with its communication where things like antigen testing are concerned.
By better, she means moving away from the typical Wellington solution of hiring a fleet of communications staff and dumping a giant one-size-fits-all communications plan on everybody.
“It can’t just be: I’m going to send an email out, or have the Māori CEO send a bulk email to tell everybody this is what we’re doing.
“When you’re in the middle of a pandemic … the last thing you’re going to do is read 46-page pamphlet, or an eight-page pamphlet.
'That’s the challenge, they actually have to pick up the phone.'
As for ACT Party leader David Seymour, like Bishop, he too is unwilling to weigh in on when exactly antigen tests should be used.
However, he can see no reason why the Government should not be allowing people to freely import tests that have been approved by regulators in places like the United States or Australia.
“There’s a chance that their [the Ministry of Health’s] prescription for using rapid antigen tests is more efficient than the Americans’.
“But it’s more likely they’re both wrong, and we should just let people access them and use them for their own purposes.”