HSE CEO Paul Reid said on Thursday that the Delta variant "poses a huge risk" to the progress of the vaccine rollout.
As of midnight on Wednesday 21 July, the Department of Health has been notified of 1,189 new cases of Covid-19 as incidence rates in every county have increased over the past week.
Of the 1,189 cases, 95 are in hospital and 22 are in intensive care units.
According to the department, daily case numbers may change due to future data review, validation and update.
According to figures published by the HSE on Thursday, there were 18 people in hospital with Covid-19 who have been fully vaccinated against the Covid-19 virus - however, details were not provided on which vaccines the patients had received.
The HSE data showed that there are 18 patients with Covid-19 who are fully vaccinated as of 8am on Wednesday.
It comes as HSE CEO Paul Reid confirmed on Thursday that 66% of adults now fully vaccinated against Covid-19 and 80% are atleast partially vaccinated.
However, Reid added that the Delta variant "poses a huge risk" to the progress made with the vaccine rollout.
“Delta poses a huge risk to this progress but one that we can meet head on. Let’s aim to support our healthcare workers having a manageable August. One that they all deserve,” Reid said on Twitter.