Co Monaghan is the only county to have a vaccine uptake rate below 77%.
Latest figures from the Health Protection Surveillance Centre reveals that 76.8% of people aged 5 and upwards are fully vaccinated in the county.
Monaghan and Donegal continue to lag behind other counties in the vaccine uptake rates.
76.8% of those aged five and upwards are fully vaccinated in Monaghan, and that figure is 77% in Donegal.
Meanwhile, 87.9% of people over 18 have been fully vaccinated in Monaghan, but only 9.7% of 5-11 year-olds are fully vaccinated.
Nationwide, 20.6% of the youngest age-group, those aged between 5 and 11, are fully vaccinated.
The figures are accurate as of the 27th of March, and defines fully vaccinated persons as those who have received two doses of a two dose schedule, or one dose of a one dose schedule.
In Co Cavan, 82.2% of people over the age of 5 are fully vaccinated, and that figure is 93.4% for those aged 18 and over.
Last year, the HSE said it was "aware" that residents in border counties like Monaghan have been vaccinated in the North.
HSE National Director, Damien McCallion claimed it was "not possible for accurate data on the numbers involved", despite "working closely with colleagues in Northern Ireland on this".
But speaking to Northern Sound, Director of Public Health North East with the HSE, Dr Augustine Pereira, said the number of Monaghan people getting vaccinated in the North is not "significant".