Scientists’ plea to drop antipathy to antigen tests
Experts say widespread use of cheaper alternative to PCR can speed up Ireland’s return to normality
THE National Public Health Emergency Team (NPHET) is coming under increasing pressure to change its opposition to antigen testing as experts underlined the key role the rapid tests can play in reopening the country.
Earlier this week, Taoiseach Micheál Martin said he believed the tests, which are much cheaper and easier to use than the currently recommended PCR tests, should be used more widely in society. Tourism, Culture, Arts, Gaeltacht, Sport and Media Minister Catherine Martin also said antigen testing may be used ahead of indoor events in July.
Health Service Executive (HSE) chief executive Paul Reid claimed that antigen testing is ‘part of the solution’, adding that while the debate is polarised ‘we all need to acknowledge a way through this one’.
Meanwhile Dr Michael Mina, an assistant professor of epidemiology at Harvard University and an international authority on antigen testing, told a Dáil committee this week that the tests were ‘very accurate, if you are concerned about limiting transmission’.
‘Any suggestion that antigen tests are 50% accurate is inaccurate,’ he said.
These comments have been backed up by health experts who spoke with the Irish Mail on Sunday this weekend.
It comes after NPHET’s Philip Nolan previously likened antigen tests supplied by Lidl as ‘snake oil’. He tweeted: ‘Can I get some snake oil with that? It makes for a great salad dressing with a pinch of salt and something acerbic. Stay safe when socialising outdoors over the next few weeks. Small numbers, distance, masks. These antigen tests will not keep you safe.’
Last month, Chief Medical Officer Dr Tony Holohan also said NPHET strongly recommends against the general public using antigen tests.
‘They are limited but they have a role to play’
‘I know these tests are available, I know people are buying. We strongly recommend against that because you can’t rely on a negative result,’ he said at the time. ‘In effect, a negative result cannot tell you anything.’
NPHET considers the Polymerase Chain Reaction (PCR) test to be the gold standard test, as does the European Centre for Disease Control (ECDC). It has both ‘high sensitivity and specificity in detecting’ Covid19, however the turnaround time for a result is 12 to 24 hours.
The ECDC states that rapid antigen tests have many benefits despite their sensitivity being lower than that of the PCR test. They can be used in a lab testing environment and also at the point of care with results in 10 to 20 minutes depending on the test, and at low cost. Antigen tests can identify pre-symptomatic patients, up to five days before the onset of symptoms which the ECDC says accounts for ‘a significant proportion of transmission’.
The ECDC agrees with the World Health Organisation that these tests should have 80% sensitivity and more than 97% specificity. It has advised EU member states to ‘perform independent and setting-specific validations of rapid antigen tests before their implementation’.
Infectious Disease consultant in Beaumont Hospital and senior lecturer in
RCSI, Dr Eoghan
De Barra, was involved in the HSE’s rapid antigen test project whose results are due to be published shortly.
Dr De Barra said the tests have a ‘role to
play’ in reopening the country ahead of sporting events and concerts planned in the months ahead.
He told the MoS: ‘I think that we should continue to explore and research the role of antigen testing in reopening. Just like every other
mitigation measure it has limitations, but by combining measures that are practicable, pragmatic and useful puts us in the best position to continue towards normal society. We need real-world data in our cultural settings to determine the value of antigen testing in Ireland. I think they have a role.’
Dr Cliona O’Farrelly, Professor of Comparative Immunology in Trinity College Dublin, said that an optimal antigen should be identified and then used widely.
She told the MoS: ‘Absolutely, antigen testing should be used, once optimal tests are identified.
‘We should have a standard procedure for testing any kit that looks halfway decent in circumstances where one would expect viruses to be circulating, e.g. schools and colleges, and comparing with PCR.’
Dr O’Farrelly suggested conducting
ongoing studies involving thousands of antigen tests a week to determine which test is best.
‘I know Simon Harris has sponsored one such study which is great, especially as he is challenging the HSE-Department of Health dogma that antigen testing is taboo but this study is a bit rigid and inflexible.
‘Still, if the study proves that antigen testing in Ireland would be useful that will be an achievement.’
Immunovirologist and lecturer at University College Cork, Dr Liam Fanning, said NPHET needs to change its position on antigen testing. Dr Fanning told the MoS: ‘We’re blue in the face saying Ireland’s opposition to antigen testing goes against what’s being used in Europe.’
When asked if NPHET intends to reconsider its position on antigen testing, a spokeswoman told the MoS: ‘The Covid-19 testing strategy, as with all elements of the public health response to Covid-19 remains under constant review and continues to adapt to emerging best evidence.’
‘We should have standard procedure for testing kit’