Thursday, 25 February 2021
Topical Issue Debate
I thank the Deputy for raising this important issue. I am responding on behalf of the Minister for Health, Deputy Donnelly. Testing and contact tracing continues to be fundamental to our response to the pandemic. It is critical to ensuring that we can identify and contain the spread of the virus.
The HSE has adopted RT-PCR as the gold standard test for diagnosing Covid-19 cases. This is the most reliable test that we have available for this purpose. In addition, appropriately validated antigen diagnostic tests are now being deployed by the HSE as a supplement to PCR testing, just as suggested by the Deputy. These tests are being used for specific indications in acute hospital settings and as part of the response to outbreaks in the community setting, particularly in symptomatic vulnerable populations and for their close contacts. Antigen detection tests, ADTs, are described as rapid and simple to perform. The validation work that has been done by the HSE and across Europe to date indicates that ADTs are most effective in detection of symptomatic cases, when symptom onset is within the past five days and when the likelihood of test positivity is greater than 10% among the target population. The validation studies available show significant disparities in test performance as against some manufacturer's claims. Many of the tests available do not meet the minimum performance requirements set by the WHO and the European Centre for Disease Prevention and Control, although that is a general finding and does not relate to the specific tests referred to by the Deputy. This means that the tests currently available are of limited use in most circumstances when testing asymptomatic populations. It is also clear that new tests and new technologies are becoming available every day.
Considerable work has been undertaken to date to evaluate the use of ADTs in an Irish context. While antigen testing will not replace the requirement for large scale RT-PCR testing for public health purposes, validation of tests is continuing in the HSE due to the potential role that ADTs have in our national testing strategy. Consideration is also being given to the use of antigen tests in asymptomatic community populations. Professor Mark Ferguson, the Government's chief scientific adviser, has been asked by the Minster for Health to set up a group to examine the use of antigen tests in the community and more expert advice is expected shortly to inform us further on the potential of these testing technologies. While we now have more tools at our disposal, it is clear that we need to deploy existing tests appropriately and be guided by scientific evidence in doing so, particularly since we are aware of the limitations of many of the tests available.
I reassure the House that the national testing policy is kept under review and we will use whatever tools are appropriate to fight Covid-19. I hope that addresses some of the Deputy's queries.