The scientists and infectious disease specialists involved in the Government’s study on COVID rapid testing were "clearly in favour" of a widespread rollout of rapid antigen testing.
The Ferguson Report, published in April, recommended the introduction of rapid tests to complement the standard PCR testing in Ireland.
The Government’s Chief Scientific Adviser Professor Mark Ferguson chaired the report and has voiced his support for antigen testing.
However, the Chief Medical Officer (CMO) Dr Tony Holohan and a number of his National Public Health Emergency team (NPHET) have continuously objected to the widespread use of the rapid tests.
Dr Holohan has now been called before a Dáil committee to explain his opposition to antigen testing after politicians heard from a number of experts backing its use.
On Newstalk Breakfast this morning, Immunology Professor Paul Moynagh called NPHET’s stance into question.
“I have been surprised in terms of how reticent we have been in terms of rolling out rapid forms of testing, including rapid antigen testing,” he said. “I think there is a place for these.”
He said antigen testing should not be compared to PCR testing as they have different uses.
“The proposal is not to use rapid antigen testing as a definitive diagnostic,” he said. “It is as a screen.
“It is a tool that we have to reduce transmission of the virus so I think there is certainly a place for rapid antigen testing.”
Sensitivity
The opposition to rapid antigen testing is due to its poor performance in detecting COVID-19 in people carrying small viral loads.
Professor Moynagh said the tests are far more effective when you are using them to detect people who are infectious because they are carrying high viral loads.
“Rapid antigen tests are not as sensitive as PCR but that depends on the level of the RNA, the level of the virus,” he said.
“So, when we look at the relatively high levels associated with infection, rapid antigen tests are very, very sensitive and are picking up at 80% or 90%.”
Infectious
He said PCR tests often pick up people carrying low levels of virus and as a result, are much less likely to be infectious.
“Frequently PCR tests will detect very low amounts of RNA fragments typically at a post-infectious stage where you can’t actually culture any infectious virus,” he said.
“So, the rapid antigen tests are picking up when you are infectious they are really sensitive at picking up cases that are at the infectious stage.”
Ferguson Report
He said the scientists and the infectious disease specialists involved in the Ferguson Report were “clearly in favour of rolling this out on fairly wide basis.”
Two of the five members contributing to the report refused to back its findings – NPHET special advisor, Dr Darina O’Flanagan and HSE National Clinical Director of Health Protection, Dr Lorraine Doherty.
The three members who backed the findings were all independent experts – UCD Microbial Diseases Professor Paddy Mallon, CUH Infectious Diseases Consultant Professor Mary Horgan and Trinity Immunology Professor Kingston Mills.
Rapid Antigen Testing
Also on the show, former Belfast Director of Public Health Dr Gabriel Scally said there is a place for antigen testing but only if they are used in a “very, very selective way.”
“If they are trying, say in a stable population in a school to pick up cases and they are testing on regular basis, that has a potential role,” he said.
“But if there are cases in a school and you are trying to use the test instead of isolating people or instead of closing down a class or taking other measures then it probably isn’t a good idea at all.”
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