Around 1,800 GPs and practice nurses are being vaccinated against COVID-19 at mass clinics in three locations today.
800 of those will be given the Moderna dose in Dublin's Phoenix Park, while teams in Galway and Portlaoise plan to administer 500 vaccines each.
GPs and their teams were chosen as they are in constant contact with patients and it is hoped they'll be giving the doses to others soon.
The HSE says its priority is to roll out the Moderna vaccine as soon as possible but it depends on supply.
It comes as an immunology expert says a short dip in supply of the Pfizer COVID-19 vaccine should not have a major impact on our rollout plan.
Immunology professor at Trinity College Dublin, Cliona O'Farrelly, believes that, despite the temporarily reduced production of the Pfizer/BioNTech jab, new vaccines will likely increase supplies over the next month.
The HSE's National Director of Quality Improvement, Dr Philip Crowley, says more of these mass vaccination clinics could be set up in the coming weeks.
"Well for a start, we'll be giving all these people a second dose in a month's time and depending on supply of the vaccine, we would hope to run more of these mass vaccination clinics probably in the next couple of weeks," he said.
The mood at the vaccination sites was described as "euphoria" by a local GP.
Dublin GP Sinead Cronin, who got the dose at the Phoenix Park location, said there was a "massive sense of relief" among healthcare workers after receiving the jab.
"I think COVID has taken a huge amount away from people, even as a society, and GPs on the frontline have gone above and beyond at all stages of the pandemic so it's great to see people and the euphoria coming out getting their vaccines," she added.
Reporting by Tom Douglas