The HSE's national lead for testing and tracing has said reports that one-fifth of Covid cases recorded here now are in fully vaccinated people is in line with what is being seen in other countries.
Speaking on RTÉ's Drivetime, Niamh O'Beirne said that in the vast majority of cases, those who are fully vaccinated and test positive for Covid-19 are reporting mild symptoms and are not getting seriously ill.
In recent days, between 18-21% of cases being reported are in fully vaccinated people, she said.
She said they're seeing a lot of people in the 15-24 age group and the 25-34 age group presenting for tests, with high volumes of people presenting for testing in Donegal, Castlebar, Galway, Cork and Tralee.
Ms O'Beirne said some of the highest positivity levels were recorded in Buncrana, and there were high levels in Monaghan and Louth as well.
Her comments came as the Department of Health was notified today of 1,522 new cases of Covid-19.
The number of people in intensive care units is 34, up three on yesterday.
There are 217 people being treated for the virus, up nine on yesterday.
In a statement, Chief Medical Officer Dr Tony Holohan said: "Over the past fortnight we have reported almost 20,000 cases.
"While 17% of these cases were in people who are doubly vaccinated, this is entirely in keeping with what we expect as an increasing proportion of our population get vaccinated. It's important to remember that this does not mean vaccines are not effective.
"While they will not prevent every case, they provide excellent protection against severe disease and significantly reduce the risk of hospitalisation."
Deputy Chief Medical Officer Dr Ronan Glynn emphasised that it is still important to follow the public health advice.
He said: "Please remember that you should stay at home if you have any cold or flu symptoms even if you are fully vaccinated, because you could still transmit Covid-19.
"If you wait to isolate until you get the results of your test, you will be much more likely to pass it on to others in your family and community. We must work together to continue to limit the spread of the disease in our communities and key to this is not attending the workplace or socialising if you have any symptoms."
Earlier, the Director of Public Health at the HSE's National Immunisation Office said that the first vaccines for those aged from 12 to 15 are expected to be administered this weekend.
Speaking on RTÉ's Morning Ireland, Dr Lucy Jessop said that registrations open online on Thursday for this age group and will require the consent of one parent or guardian.
Dr Jessop said a strong uptake is expected as there is enthusiasm among parents about vaccinating their children.
She said that children will be vaccinated with mRNA vaccines, either Pfizer or Moderna, and each child will require two doses over three to four weeks.
Dr Jessop said that most children aged 12-15 recover well from Covid-19, but some require admission to hospital or to intensive care, while some children can develop Long Covid or develop a rare multi-system inflammatory condition.
She said that no additional safety concerns have been reported where these vaccines have been used among 12 to 15-year-olds.
Dr Jessop said the mRNA vaccines have been used on adults since December and 4.4 billion doses of Covid-19 vaccines have now been administered across the world.
She said that it is important for parents and children to look at up-to-date information on vaccines before choosing to be vaccinated.
Meanwhile, HSE Chief Executive Paul Reid said almost 9,000 people received a vaccine dose at a walk-in centre over the weekend.
In a tweet Mr Reid said: "2/3 of these hadn't previously registered. All age groups were represented and on occasions full families attended.
"We're on the final leg of the vaccination programme now."
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A very busy testing weekend. Over 23,000 swabs taken in our community testing sites over the last two days. This level of weekend testing was surpassed only once before in early January. Appointments available online or walk in. @HSELive @paulreiddublin— Niamh O'Beirne (@NiamhOBeirne) August 8, 2021
Meanwhile, Kazakhstan has been added to the Mandatory Hotel Quarantine list from 4am this Friday.
People arriving into Ireland from the country, who are not yet fully vaccinated, will have to quarantine for 14 days.