People over 16 will start receiving a Covid-19 booster from today.
The rollout comes as cases of the virus reach record levels and put pressure on the hospital system.
From today people aged 16 to 29 will start receiving a Covid-19 booster at vaccination centres.
Clinics for the age cohort are operating today in Tipperary, Clare and Limerick, where they'll receive a single dose of the Pfizer vaccine.
Additional centres are expected to open to the age group throughout the week.
Alternatively, booster appointments are available through GPs and pharmacies.
It comes as yesterday saw the highest number of Covid cases reported since the start of the pandemic, at 23,281.
Meanwhile the HSE says it expects non-essential care to be reduced this coming week, as hospitals struggle to deal with high number of staff absences due to the virus.