A single outbreak of Covid-19 among students in the west of the country led to 442 further cases in over 200 separate household outbreaks.
Speaking at Thursday evening's Department of Health briefing on Covid-19, HSE West Public Health Director Dr Breda Smyth said of those 442 cases, 179 were linked to multiple household clusters, where there were multiple households involved.
224 households in total were affected from the initial outbreak that has been traced to students.
Dr Smyth said the movement of young people through the region as a result of socialisation was among the primary reasons for transmission.
“There was also a cluster in another part of the country as a result of this outbreak,” she said.
In addition to spreading infection in the community, Dr Smyth said there were knock-on effects in other areas with associated exposure and transmission in the hospitality sector, retail sectors and vulnerable settings.
Earlier this week, the University of Limerick (UL) condemned students who attended a large gathering in a housing state near the university on Tuesday night amid a student outbreak that has seen almost 280 confirmed Covid-19 cases to date.
Footage shared on social media showed dozens of people singing, dancing and drinking, most without masks, in a housing estate that is heavily populated by students of UL.
The university is conducting an investigation to identify any students who took part in the gathering with those involved facing suspension, pending a full investigation, or possible expulsion from the university.
In a statement, Public Health Mid-West said it encourages students to engage "open and honestly" with contact tracers should they receive a call.
"Both testing and contact tracing are confidential processes, and are there to protect you, your household and your community."