Booster vaccines have been approved for everyone aged 16 or older.
However, most people will still have to wait five months after their second dose to get a booster.
NIAC made the recommendations, which have now been approved by the Government.
Pregnant women will be prioritised for boosters.
Those aged 40-49 years will be next in line, followed by younger adults in ten-year age groups (similar to the initial rollout).
Anyone aged 16-39 who received the Janssen vaccine, however, can be offered an mRNA booster dose "irrespective of their age" three months after their first dose.
It means younger adults who received the one-dose vaccine will be able to get their booster ahead of those who previously received the Pfizer or Moderna vaccines.
Most other people will be eligible for a booster five months after their second dose - meaning it will still likely be several weeks or months before they need boosters.
Those who have had COVID-19 will have to wait six months after infection for a booster.
Booster vaccines had already been approved for all over-50s and anyone with an underlying health condition.
Health Minister Stephen Donnelly said: "I am accepting and authorising these latest recommendations on the basis that a significant amount of planning will be required to operationalise these booster doses.
"No-one in these newly approved age cohorts has yet reached the recommended gap since the second dose.
"I am also accelerating the booster rollout to those with underlying conditions and those in their 60s.”
HSE CEO Paul Reid says the plan to administer booster jabs to people over 50 will begin in the middle of next month, earlier than previously expected.
Walk-in sites for people aged 60-69 and healthcare workers will be operating this weekend.
