Dr. Tony Holohan:

I am grateful for the invitation to attend this meeting. The Chairman has outlined the list of people accompanying me. I am joined today by Dr. Glynn, deputy CMO; Professor Nolan, chair of the modelling group, Dr. de Gascun, consultant virologist and director at the National Virus Reference Laboratory; Professor Keogan, consultant immunologist and national clinical lead for pathology; and Professor Cormican, consultant microbiologist and national clinical lead for antimicrobial resistance and infection control.

I am glad to report that the Covid-19 epidemiological situation in Ireland remains encouragingly stable and currently gives rise to a broadly positive outlook, notwithstanding an ongoing level of uncertainty due to the threat of variants, which are of concern throughout the world. A significant proportion of the adult population in this country remains to be fully vaccinated notwithstanding the good work of the HSE in that area. Our progress has been made possible largely due to the great sacrifices of people in this country and their continued high levels of adherence to the public health measures. Their compliance with those public health measures is what has controlled the disease so far, along with the progressive impact of the national vaccination programme.

We continue to target the public health response in order to most optimally in our judgment mitigate the impact of the pandemic, including as it relates to testing for SARS-CoV-2, which is the virus that causes Covid-19. However, breaking chains of transmission cannot be achieved through testing alone. Ultimately, breaking chains of transmission depends on the extent to which appropriate follow-on, and individual and public health actions are implemented and supported by a wider, comprehensive public health response. As I have said, we have largely seen that in this country. That said, access to timely and accurate Covid-19 testing is an essential component of a multifaceted response strategy which supports case identification, contact tracing, clinical management of cases, infection prevention and control, and disease surveillance including for emerging variants.

In this country to date, testing for the SARS-CoV-2 virus has been primarily based on a robust and agile PCR testing capacity that has been built up to approximately 175,000 tests per week. PCR remains the most accurate and internationally recognised gold-standard diagnostic test for SARS-CoV-2. Our PCR testing capacity is focused on high-yield target groups in the population, such as symptomatic persons or close contacts of cases, along with higher-risk settings and specific indications to limit the importation of Covid-19 as a result of essential travel to this country.

In addition, since late March 2021, free walk-in testing pathways have been established to provide access to free PCR testing for asymptomatic individuals in various locations around the country where there is deemed to be a public health need, for example, due to a high disease incidence in a local community. The Chair will be well familiar with that in Limerick.

In addition to PCR testing capacity, substantial work has also been undertaken by the HSE to examine the potential role for rapid testing within the wider pandemic response. As part of this work, the HSE has performed independent and site-specific validation in Ireland of a number of rapid antigen tests. On foot of this work, the HSE recommends that the use of rapid antigen tests be considered as a diagnostic test in symptomatic people, when a public heath risk assessment determines that the rapidity of results is of utility as an adjunct to the available PCR capacity. For example, in vulnerable communities where there is follow-up of those positive results that are likely to be challenging, or as a supplement to PCR testing in the event of inadequate PCR capacity to meet requirements, which is a situation that we do not find ourselves in at this point in time.

International evidence to date, including two recent major international publications from the Infectious Disease Society of America, published this month on 5 June, I think, and the Royal Statistical Society in the United Kingdom, which was also published this month; the recent Covid-19 Test Validation Summary Report that was published by the HSE earlier this week; and, existing guidance from the World Health Organization and the European Centre for Disease Prevention and Control, ECDC, all indicate that rapid antigen tests typically perform best in symptomatic individuals and in settings of high disease prevalence, and less well in asymptomatic persons in low prevalence situations.

Based on existing evidence, the use of rapid antigen testing may be considered in high-prevalence settings such as outbreaks where the pre-test probability of individuals being infected is high, and where more rapidly available results may support PCR testing through the early identification of cases and implementation of appropriate follow-on public health actions. The HSE has already made rapid antigen tests available for deployment in such scenarios, where deemed appropriate by local public health teams.

Rapid testing, with antigen testing, may also be considered in higher-risk environments for transmission of Covid-19 as may exist in, for example, meat processing plants. Substantial work has been conducted to evaluate the results and use of rapid antigen tests in asymptomatic workers in this setting, under strictly controlled processes. Both the HSE and the Department of Health have supported the piloting of rapid antigen testing in meat processing plants led by the Department of Agriculture, Food and the Marine.

The HSE has also made rapid antigen tests available for use in acute hospital settings, if deemed an additional utility by the relevant institutions in the context of access to typically quick turnaround of PCR testing on site. In addition, the Department of Health has supported, and does support, the development of a collaborative pilot now in place by the Department of Further and Higher Education, Research, Innovation and Science, the Science Foundation Ireland, SFI, the HSE, HIQA and a number of third-level institutions. It is a validation study to examine the potential applicability of different rapid antigen testing approaches in third-level settings. We look forward to reviewing the output from that study. Separately, the HSE is also progressing plans to pilot rapid antigen tests for use in childcare settings as well as in a number of third-level institutions.

While there may be a potential utility to be realised from the use of rapid testing in controlled environments, and this may further evolve over time, there is still much we need to learn about these tests and their actual, as opposed to hypothetical, benefits and limitations. As stressed by the authors of the Royal Statistical Society Report in the UK, which I encourage members to read, the proper assessment of the suitability of Covid-19 tests has been neglected to date, with many tests brought to market without appropriate real-world evaluation or well-designed studies evaluating tests in real-world settings where they are used, and this must become standard practice. In particular, while the aforementioned indications and pilots may be considered as “red light” rapid testing activities, picking up additional cases in a timely manner, and appropriately integrated into the wider public health response, significant caution is urged in regard to any move towards employing rapid antigen testing for “green light” or “enabling” activities that we would otherwise deem to be unsafe, particularly while not accounting for the prevailing epidemiological situation.

Given the limitations of such tests along with the current lack of a substantive supporting real-world evidence base, the hypothesis that antigen testing could be a precursor or enabler for the safe recommencement of certain activities, which would otherwise be deemed not to be safe given the prevailing epidemiological situation, poses several risks both to the individuals engaging in those activities, and those around them, as well as to the wider public health response.

As the evidence evolves, and assuming that this evidence is supportive of the use of rapid antigen testing, we are more than willing to support its further use where appropriate evaluation indicates that it can bring added benefit in the pandemic response. Ultimately, based on knowledge to date, the safest way for us to reopen society, including international travel, will be to continue to control the incidence of the disease, and we are making encouraging progress in that regard, through a range of public health measures that are continuously reviewed, as we do, along with progressing the national vaccination programme to ensure as many people as possible within the population are protected through immunisation. That is our current policy and it is working.

Once again, we thank the committee for extending an invitation to meet today to discuss the Covid-19 testing strategy in relation to travel. We are happy to take any questions on the strategy or on anything else.