Ireland, which has recorded no new deaths from Covid-19 for two days, could run into trouble again if the weekend scenes of heaving revellers enjoying "takeaway pints" in Dublin city are repeated, public health doctors warned.
Acting chief medical officer Dr Ronan Glynn said: "If gatherings like that continue, then it is inevitable that we will run into problems.
"The virus is still out there, we are not immune - very few of us have had this."
A further four people were diagnosed with the virus yesterday while 19 patients are being treated in hospital, including 10 in intensive care.
Dr Glynn said the driving down of infection left Ireland in an almost "uniquely good" position but there was always the risk of ending up where we were months ago if individuals did not follow basic guidelines.
They would jeopardise the lives of the sick and vulnerable and threaten the chances of children returning to school in September, he warned.
Dr Colm Henry, HSE chief clinical officer, said: "Vulnerable and older people rely on the actions of each and every one of us for their safety. If the virus begins to spread in our communities, these fellow-citizens will be most at risk."
Over the past 14 days, there were 141 new cases of the virus and the median age of people who contracted it was 37 years.
As people embark on home holidays around the country, it emerged there were new cases in 20 counties including 58 in Dublin and 24 in Kildare.
Sligo, which is a county with low levels of infection, had 18 more cases due to a single person returning there who tested positive and ending up passing the virus on to their immediate family and extended family.
Dr Glynn defended the decision to not provide a list of countries this week with low levels of virus that people can travel to without having to quarantine on their return.
He said the last few weeks were more "volatile" internationally due to countries having large outbreaks.
Asking people not to travel abroad for their summer holidays, he said the "global situation is changing rapidly and we need to see where it goes".
Dr Glynn also expressed concern about the numbers of people who were in contact with a person who caught the virus but who refused the offer of a test.
"From mid-May to the end of June, 35pc of those identified as a close contact of a confirmed case did not take up the offer of a test. Every case has the potential to turn into a cluster, which in turn has the potential to spread through a community.
"If you are identified as a close contact, please take up the offer of a test without delay."
Asked about private hospitals charging patients for Covid-19 tests in advance of being admitted for procedures he said: "I don't think it is acceptable that anyone is precluded from treatment in the context of a global pandemic."
If it got out of control again, it would have significant consequences for both public and private hospitals.
Research carried out on behalf of the Department of Health shows "a higher level of overall worry among the population" about Covid-19.
There is a growing proportion of people who now believe there will be a second wave.
The nationally representative sample of 2,004 people conducted on behalf of the Department of Health revealed almost three-quarters think that there will be a second wave.
This is a rise of 20pc in the past month.
The findings revealed that 41pc the population now believes that the worst of the pandemic is behind us.
But many of us think there are even tougher times ahead, with as many as 32pc saying the worst is yet to come.