Covid: Antigen testing will be used as testing numbers rise, says HSE

Close contacts will use this system ‘to self-test on four days’

Antigen testing will be deployed in addition to PCR testing, the HSE has said. File photograph: iStock

Antigen testing will be deployed in addition to PCR testing as the number of people presenting for testing rises, the Health Service Executive (HSE) has said.

Hospitals are preparing for a surge in Covid-19 cases as the Delta variant fuels a faster-than-expected spread. There were 994 new cases confirmed on Thursday night – around two weeks earlier than when 1,000 cases a day were expected to occur.

Niamh O’Beirne, HSE national lead for testing and tracing, told RTÉ radio’s Today with Claire Byrne show on Friday that antigen testing will be used for close contacts who will have to self test four times, on days zero, five, seven and ten. Those people will also have to self isolate.

There had been a significant rise in the numbers presenting for testing at community testing sites in recent days, she said, with an average positivity rate of 5.9 per cent, rising to 15 per cent in some locations. This compared with positivity rates of up to 50 per cent last January, she explained.


At present the highest positivity rates were in Roscommon, Donegal, Wicklow, Cavan, Louth, Monaghan with the majority in the 21-30 age group.

Ms Beirne said much of their planning relied on modelling by the National Public Health Emergency Team (Nphet) that allowed her teams to prepare to increase capacity as required. Some of the possible scenarios were “very startling”, she said.

If the level of demand for testing were to rise to 120,000 per day, PCR testing would not be possible – which meant that plans this time included antigen testing for close contacts, Ms Beirne said, adding a box of five antigen tests would be sent to each close contact, and their results would be monitored.

The demand for tests will increase in the next two weeks, she said. The initial “lift” in numbers had been higher than modelled.

In January, even though the numbers were very high, all close contacts had been contacted, she said, even on the worst days when the HSE was coping with 6,000 to 7,000 cases, but the calls to those contacts were shorter to allow more calls to be made, she added.

Pop-up centres would be deployed to bigger testing centres on busy swabbing days, said Ms O’Beirne as it was more effective to test 500 people at a bigger testing site than 19 in a smaller location. If there was a surge in a village then people would be directed to a larger mass testing centre, she said.

Ms O’Beirne encouraged the public to continue to use the Covid app and to “tell us all their contacts” as it was now known that people had more contacts.

The vaccination programme was helping the situation, she added. “It is the unvaccinated that are contracting the virus.”

Of the 107 outbreaks in the last week, two were in hotels; in the previous week hotels accounted for eight of 121 outbreaks, she said. Most of the outbreaks were from group settings, house parties and family gatherings, with travel cases on the increase, she said.

Travel accounts for approximately 10 per cent of cases at present, Ms O’Beirne said. “Flights are complex for us,” as manifests and travel-locator forms all have to be followed up. The number one cause [of contraction] is close contacts, flights are second and social gatherings are third, she added.

The HSE had a supply of antigen testing kits ready if required to be deployed, while the testing and tracing system will be able to adjust its capacity to cope with 15,000 to 16,000 calls per day, she said.

Earlier on Friday, Prof Liam Fanning, a professor of immunovirology at University College Cork, said the fact the HSE is now using antigen testing for close contacts of cases shows it is essentially “side stepping” Nphet.

Chief Medical Officer Dr Tony Holohan has been vocal in expressing his concerns about the limitations of antigen tests.

However, Prof Fanning told Newstalk Breakfast that ruling out antigen testing was like “hurling with one hand”.

The HSE’s clinical lead on contact tracing, Dr Greg Martin has explained that antigen testing will be used only when PCR testing has reached capacity of 20,000 tests per day.

Speaking on RTÉ radio’s News at One, Dr Martin said that the contact tracing system had been working “full steam ahead” in recent weeks and while the workload had increased the increase had been anticipated and plans had been put in place.

The system had been set up to deal with high volumes, he said and staff were “well able” to continue their important work. Even though case numbers were up, the level of hospitalisation had “not hit as hard” as during previous waves in the pandemic.