The State's chief medical officer Dr Tony Holohan privately expressed strong concerns about the wider use of antigen tests just weeks before they became a key part of the Government's response to Covid-19.
In November when Minister for Health Stephen Donnelly was considering subsidising antigen tests, Dr Holohan privately warned him against "incentivising" the use of antigen tests with a subsidy as it "gravely risks" further increasing rather than reducing transmission of the disease because of the high level of "inappropriate use" of the tests identified by research.
Mr Donnelly pushed back, telling Dr Holohan that “an immediate public awareness campaign” was urgently needed to inform the public on “how and when to use” antigen tests as it was important to use “every tool available to us” in the fight against the virus.
Support for the greater use of antigen testing – a quicker and easier test used by the public but less accurate than the official PCR test – has long been the source of tension between the Government’s public health advisers and those who see it as another means to manage Covid-19.
Antigen testing has gone from being dismissed as "snake oil" by Prof Philip Nolan, chair of the National Public Health Emergency Team's modelling group, last year to forming a major plank in the public health response to Covid-19 in the most recent Omicron wave of infection.
Correspondence between the CMO and the Minister dating back two months shows robust exchanges between the two men on the subject, with Mr Donnelly pushing Dr Holohan for wider antigen testing.
The letters were released by the Department of Health to The Irish Times under the Freedom of Information Act.
On November 17th, the Minister emailed Dr Holohan saying that representatives of private nursing homes had been in contact to request that antigen tests be deployed in nursing homes.
The CMO emailed back two hours later in an email with the subject “Urgent – Update on Antigen Testing”, saying that new data from research company Amárach showed that a majority of people using antigen tests were symptomatic and that a majority of people with Covid-like symptoms were using antigen tests “contrary to public health advice”.
He warned that symptomatic people were interpreting a “not detected” antigen test result as a “green light” with just one in three going on to self isolate and arranging a PCR test.
Dr Holohan told the Minister that GPs and public health doctors nationally were “strongly echoing these concerns” and “noting the potential for unintended consequences as a result of inappropriate use of these tests”.
He said that public health doctors were reporting “several examples” in childcare facilities and schools where symptomatic people had used a “not detected antigen test result to “as a green light to attend that setting, thereby placing other children/adults at unnecessary risk”.
On November 19th, Mr Donnelly replied to the CMO saying that he appreciated the concerns “and indeed share some of them” but added that there was “clearly an urgent need to improve public communications” on how antigen tests were being used.
“There has not yet been sufficiently clear and accessible guidance on how and when to use these tests. Nphet has highlighted the need for strong communications on rapid tests, as has the expert group. We need to ensure this happens quickly,” he said.
He said that there was an urgent need for “an immediate public awareness campaign”.
“We all know there is no silver bullet here, but we must use every tool available to us,” he said.
“Once the HSE and department provide the public with the necessary information around the appropriate use of rapid tests, I’m confident people will be well able to follow the guidance – just as citizens in other countries are doing.”
He concluded: “Clear communications needs to happen urgently and irrespective of any subsidisation as people are already using these tests and we have a duty to inform them.”
Less than an hour later, Dr Holohan replied, saying he fully agreed with the need for “stronger communication” on the appropriate use of the tests, particularly given the “very concerning data” suggesting that most people taking them were using them “contrary to public health advice”.
“My considered advice to you as Chief Medical Officer is that incentivising the use of these tests at a time when there is such poor understanding represents a very significant risk to the effectiveness of all of our core public health measures and actions, and gravely risks further increasing transmission,” he said.
“Any scheme that incentivises further use of antigen tests should not be progressed until there is much greater understanding of their appropriate use amongst the general public.”
Three days later, Dr Holohan issued fresh public health advice in response to a significant and rapid increase in the spread of Covid-19, particularly among unvaccinated primary school children, telling people not to rely on the results of an antigen test if they have symptoms.
At the end of November, Mr Donnelly dropped plans to introduce a subsidy for antigen tests, saying that such a move had become “unnecessary” as the price of testing kits had fallen.
Details of Dr Holohan’s warnings were reported in November but not the full content of the exchange of emails between the CMO and the Minister reflecting their differences over the antigen tests.
By the end of December, with the virus spreading at record levels overwhelming the HSE’s PCR testing system, any reservations about antigen testing were abandoned.
Nphet issued new guidance saying that anyone aged between four and 39 with Covid-19 symptoms should undertake regular antigen tests rather than book a PCR test and only seek a PCR test if they test positive on an antigen test.
It was the first time that Government’s public health team advised people showing symptoms of Covid-19 to undertake antigen tests at home rather than seek a PCR test with the HSE.
Two weeks later guidance changed again with Nphet advising that people aged between four and 39 did not need to seek a confirmatory PCR test even if they tested positive on an antigen test.
Fully vaccinated close contacts of Covid-19 cases were also told to take regular antigen tests over seven days instead of having to self-isolate for five days.
Nphet subsequently started publishing daily figures on the number of positive antigen tests reported by the public alongside the official Covid-19 cases confirmed by PCR tests.