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What does Nphet know about antigen testing that the rest of the world doesn’t?

Many disagree with Nphet, among whom are the WHO and European Commission

Here we go again. The Covid case numbers are rising. The positivity rate is over 10 per cent. Professor Philip Nolan of the National Public Health Emergency Team (Nphet) is talking about knife edges, and the deputy chief medical officer Ronan Glynn is worrying about key indicators. On RTÉ Radio 1, Claire Byrne is asking if we can keep schools open. There is a nauseating sense of deja vu about it all, and a creeping suspicion that nobody quite knows why we're back here.

Meanwhile, the rest of Europe – with lower vaccination rates and lower caseloads – is basking in relative normality.

But there is one significant difference between us and other countries that we haven't been talking much about. Other countries are widely using antigen testing. Germany and France were offering it free up to this week, when a charge was introduced to encourage vaccination. In Italy, unvaccinated employees have to produce a negative antigen test result every three days, or a PCR test every four days. Greece offers free antigen testing to children under 12, and those who can't be vaccinated.

When [Irish people] were asked to take the vaccine, they did, in world-beating numbers. But for some reason, that same responsible, rule-following public is not to be trusted with antigen tests

New Zealand is providing antigen tests for frontline workers. Singapore is offering supervised self-swabbed antigen tests at 25 centres for those who want to gain entry to indoor venues. Denmark relied heavily on rapid testing when virus levels were high. Now, with the Minister of Justice declaring Covid-19 "no longer a socially critical disease", vaccination centres have reverted to PCR testing only. US president Joe Biden recently announced a $2 billion investment in rapid, at-home tests. In Britain, you can pick up an antigen test for free in a pharmacy or a library, or order up to seven a day to be sent to your home.

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So what does Ireland – or, more specifically, a few senior figures in Nphet – know that the rest of these countries don't? The closest thing we have to an official position on antigen testing is that it is something akin to, as Nolan put it earlier this year, snake oil. The last official pronouncement on the subject was in June, when chief medical officer Dr Tony Holohan said that though antigen tests had uses in strictly controlled settings, "there is still much we need to learn about these tests and their actual" – as opposed to hypothetical – "benefits and limitations". He has previously warned about the dangers of "individuals getting inappropriate reassurance" from a negative result.

Let’s unpick this for a moment. When Irish people were asked to stay home, they did, showing remarkable compliance through one of the longest lockdowns anywhere. When they were asked to take the vaccine, they did, in world-beating numbers. But for some reason, that same responsible, rule-following public is not to be trusted with antigen tests.

A study at University College London has found that antigen tests were more than 80 per cent effective at detecting any level of Covid-19 infection

As compliant as we’ve been, it’s hard to imagine there would be the same high levels of support for another lockdown. So we’re left to try and limit Covid’s spread and protect the health service – the goal we keep being reminded we’re working towards – by testing and tracing. And yet, for reasons that are frankly difficult to understand, we’re refusing to capitalise on two powerful weapons in that arsenal. Tracing of primary school children was suspended in September. And we’re relying exclusively on slow and expensive lab-based PCR testing, instead of a test that costs about €6 in pharmacies, can be administered at home and gives a reliable result in 15 to 30 minutes.

The good news is that the evidence Holohan claims to have been holding out for is now here. Since rapid testing was introduced in secondary schools in March in Britain, the BBC reports, 103,409 came back positive. Of those 79,000 were confirmed by PCR; 7,647 follow-up PCRs were negative. A study at University College London has found that antigen tests were more than 80 per cent effective at detecting any level of Covid-19 infection, and more than 90 per cent effective at detecting those with the highest viral load. In other words, rapid tests are at their most effective exactly when you most need them to be.

Holohan might well make the point that, despite the UK’s love of antigen tests, its caseload is going up. But the UK has also lifted almost all remaining mitigation measures. Nobody is saying antigen tests are a panacea; what they are is an important tool.

Could it be that those who opposed the introduction of antigen testing don't want to accept they were wrong, just like they didn't want to admit being wrong on masks?

Here are some groups that disagree with Ireland's stance on antigen tests. The World Health Organisation says antigen testing "can offer a faster and less expensive way to diagnose active SARS-CoV-2 infection". The European Commission says they have a "crucial role". The US Centers for Disease Control says "antigen tests have comparable sensitivity to laboratory-based [tests] when viral load in the specimen is high and the person is likely to be most contagious."

Interestingly, the antipathy among some public health figures towards rapid testing is not universal. Last March, the Government's chief scientific adviser, Prof Mark Ferguson, led a team of senior scientists to look at the issue. Their report recommended the Government "start immediately" rolling out a series of pilots in schools and expanding testing in meat plants and other settings. "The evidence based for deployment of rapid tests designed for use in asymptomatic populations is growing... it is important that Ireland is in a position to take advantage of these developments." Minister for Health Stephen Donnelly agreed with the findings that rapid testing had "an important role to play". Since then, it has been used in nursing homes, but few other public settings.

Could it be that those who opposed the introduction of antigen testing don’t want to accept they were wrong, just like they didn’t want to admit being wrong on masks? And if so, is that a good enough reason to jeopardise reopening plans, or to risk a fifth wave?