This is my home town. I think the 99.7% figure has been overstated. My understanding is that it has been calculated as:

(vaccinations carried out in waterford) / (population of waterford)

Waterford is a regional hub for the south east of Ireland. There are many vaccinations for people who reside outside of Waterford carried out in Waterford, including from counties kilkenny, tipperary and carlow.