Almost 96% of adults in Co Mayo have now received at least one dose of a Covid-19 vaccine.
The latest data from the HSE shows that Monaghan and Donegal - the two counties with the highest Covid-19 incidence rate - have the lowest rates of vaccination.
In Monaghan, 83.5% of adults have received at least one dose, while in Donegal, the take-up is less than 85%.
These two counties currently have the highest incidence rates of the disease.
In the West, 95.7% of adults in Mayo are vaccinated, with over 96% in Sligo, and over 94% uptake has been recorded across Galway and Roscommon.
In a European context, the HSE says Ireland ranks third in the EU for the proportion of the population with at least one dose of a vaccine, after Portugal and France.
Only one in 5 Irish children are at least partially vaccinated here, while four out of 5 young adults aged 18-24 have received at least one dose - higher than the EU average for both age groups.