Delta is now the dominant coronavirus variant in Ireland and is most prevalent in younger people, with almost half of cases in those aged 19-34.
Yesterday, Taoiseach Micheál Martin summed up the situation by saying that Ireland is in a race between the Delta variant and vaccines.
Professor in Immunology at Trinity College Dublin Derek Doherty says this is primarily because the 19-34 age group has not yet been vaccinated and that younger people are "possibly more inclined to socialise and get into close contact with each other.
"The big risk is that they are becoming infected, which slows down the whole pace of the race against the virus with the vaccine," Prof Doherty added.
Younger people should be vaccinated as a priority in order to curb the spread of the virus, according to Prof Doherty who says "we are no longer talking about hospitalisations and serious disease, we are talking about the number of people who are being infected and if we want to end the pandemic I feel we should immunise the children and the teenagers".
In relation to the delay in reopening indoor dining, he says it "will make a difference".
"If you allow people to dine indoors they will get more infections," he says, but adds that whether it is going to make enough of a difference when all aspects are considered is hard to say.
"Definitely as a scientist I would say it will lead to more infections if we have indoor dining, but it will also make a lot of people very happy."
The Government's initial target - based on supplies - was for 82% of the adult population to have received a first dose of a Covid vaccine by end of June.
However, due to supply shortfalls, this has since been revised down, with the target now to reach 70% by the end of July.
Taoiseach @MichealMartinTD says we are in a race between the Delta variant and vaccines, and we must do everything we can to make sure the vaccine wins. pic.twitter.com/Mn7RRgZiMX— RTÉ News (@rtenews) June 29, 2021
Dean of Public Health in the Royal College of Physicians Ireland Professor Emer Shelley believes the main priority with the vaccine roll-out should now be to "continue the age-related roll-out that we have had, aiming to get as many people vaccinated as quickly as possible and that as we all know is dependent on supplies".
Prof Shelley says this is the best way to protect vulnerable groups and "also when cases are imported it means the people they come into contact with are likely not to get infected and not to transmit the infection onwards.
"The vaccination isn't just for the next few months, this is laying the foundation for immunity for the long-term whatever way the Covid-19 pans out," she says.
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And the vaccine roll-out continues to gather pace.
Over 4.1 million doses have so far been administered, with 67% of adults - or two and a half million people - having received one dose of a vaccine.
While 44% of adults (1.67 million people) are fully vaccinated.
The effort to get the population fully vaccinated has been boosted by NIAC's recommendation that those aged 18-40 can now be given the AstraZeneca and Johnson & Johnson (Janssen) shots.
The HSE says it will take a couple of days to consider this advice and will then produce a revised plan quickly.
Around 200,000 doses of the Janssen vaccine have already been received, with 80,000 more doses expected in July.
While around 65,000 AstraZeneca vaccines are due to arrive here in the next two weeks.
Pharmacists are already administering Janssen doses to people aged 50 and over and are in talks with the HSE about also giving jabs to new cohorts who have become eligible.
NPHET has described Delta is a "substantial threat".
It is more transmissible than other Covid variants and is more of a risk to those not fully vaccinated.
In Ireland what we do not know yet is how much this will translate to increased hospitalisations, deaths, and long-term complications.