Pharmacists have reported an overwhelming level of interest from younger people in receiving the Johnson & Johnson COVID-19 vaccine.
The Irish Pharmacy Union says its members have received ten calls for every available inoculation from people aged 18 to 34.
The union added that there is no sign of vaccine hesitancy among the younger age group, who can get the one-shot jab in a local chemist from Monday.
Registration for the younger age cohort to get the Janssen vaccine opened on Friday following an announcement from the Minister for Health Stephen Donnelly.
Ciara Toolen, superintendent of Adrian Dunne Pharmacies, was one such pharmacist reporting an incredible amount of interest from people to sign up to receive the injection.
She told Aideen Finnegan on Newstalk Breakfast Weekends that 25,000 people registered on Friday across 12 of the group's pharmacies and it has been a "pretty hectic" 48 hours since then.
"On Friday, all the pharmacists around the country were having their breakfasts and listening to the announcement being made over the radio so I think we were all a bit shocked," Ms Toolen said.
"We really didn't know what we were heading into in the pharmacies that day, all the uncertainties of vaccine supply and the logistics of how we were going to go about vaccinating this age group.
"In saying that, we're all delighted, it's a really positive announcement for Irish pharmacies."
Ms Toolen added that pharmacists received no official notification from their union or the HSE prior to the announcement being made, which only added to the surprise.
Some people who registered on Friday could be left disappointed in the days ahead, however, as pharmacies that are low on stock of the Johnson & Johnson vaccine will not get fresh supplies until the middle of the week.
"We're currently vaccinating people over 50 with the Janssen vaccine so in some of our pharmacies we have been able to vaccinate between 30 to 40 a day," she said.
"Obviously in some of our pharmacies we would have two pharmacists on duty, so one pharmacist would be able to dedicate their time to solely vaccinate.
"In other pharmacies where there's only one pharmacist on duty we might be a little bit slower, they might go through ten or 20 a day.
"But at the end of the day, the number of vaccines we can actually provide is very limited to the supply we get from the HSE.
"We were told on Friday that we're due to get another delivery of the Janssen vaccines next Wednesday, Thursday or Friday but every pharmacy will be receiving 50 doses.
"We really are hoping the HSE will divert more vaccines to the pharmacies so we can roll out the vaccination process quicker, but it's very much limited to the number of vaccines we get so fingers crossed, every week we'll be getting an additional supply."