Pharmacies are experiencing a "considerable" rise in sales of home antigen tests, with demand expected to increase in the run-up to Christmas, according to the Irish Pharmacy Union (IPU).
However, as the popularity of the tests continues to grow, GPs have noted a worrying trend in patients treating negative results as confirmation they have not contracted Covid-19 and neglecting critical guidelines.
With the debate around the use of antigen, or lateral flow, kits and their potential contribution to fighting disease spread well under way, anecdotal evidence shows the public have already embraced them en masse.
"The demand has increased very considerably lately... to the extent that some pharmacies are running low on stock," said Darragh O'Loughlin, IPU secretary general.
His members are expecting this trend to continue alongside rising case numbers as people prepare for Christmas and the associated rise in social mixing. But Mr O’Loughlin echoed the warning of public-health doctors that the tests are just an additional weapon and not a confirmation of safety.
“People should not derive a false sense of security” from negative results, he said, highlighting a mistake that is, in many cases, already being made.
Many of those purchasing home testing kits are not asking pharmacy staff for advice on how they should be used or interpreted.
The concern held by many in the healthcare sector is that people will increasingly jettison both PCR testing and other protocols once they have received a negative home kit result.
Dr Denis McCauley, chair of the Irish Medical Organisation’s GP committee, said up to 70 per cent of patients presenting with symptoms of respiratory illness were convinced they were clear of Covid on the back of negative lateral flow tests.
“That’s a big problem,” he said. “What they’re being used for is as a substitute and an interference with the pre-existing protocols and that’s where they fall down.”
Dr McCauley’s concerns echo those of the National Public Health Emergency Team (Nphet), which has long been sceptical of an ability to both adopt antigen testing and maintain public understanding of their limitations.
“[People] are blindingly adhering to the negative test to allow them to get on with their lives when in fact we know that that is not what they’re supposed to be doing,” he said.
“Every day everybody rings to say: ‘I have a sore throat, my lateral flow test is negative, can I have something for my sore throat.’ We are seeing it every day: negative lateral flow test means a) I am Superman, I don’t have Covid; and b) I can do what I want.”
Dr McCauley believes that only when comprehensive data is derived from the Health Service Executive’s close-contact antigen test distribution system – finding how many positive tests they discover among asymptomatic cases in the population – will their true added value be understood. But this is likely to take months.
A spokeswoman for the Department of Health said Nphet keeps all latest evidence relating to rapid antigen detection tests in all settings under review. She noted Minster for Health Stephen Donnelly has asked the HSE to establish antigen testing of close contacts in specific primary school settings.
While there are reservations about an expansive public use of such home tests, and the consequent behaviour, University College Dublin virologist Dr Gerald Barry said the issue is one of public education.
A proponent of antigen testing as part of the public-health response, Dr Barry said people’s misinterpretation of results, or overconfidence in them, was the product of an information deficit.
“It’s a reflection of the lack of understanding in the general population of what antigen testing is and what it tells people,” he said, repeating his calls for an information drive.
“We need to stop telling them not to [use them] because people are not listening; [they are] using them and they are available.”
Required information, he said, includes exactly when tests should be used and how often, but that other protocols should be adhered to and anyone with symptoms needs to take a PCR test.
“I think they have to be seen almost like masks. We know masks help but they aren’t foolproof.”