Ireland has the lowest incidence of coronavirus in Europe, Tony Holohan said.
The chief medical officer praised younger people's "enormous achievement" in driving down the rate of infection.
Three more people have died with Covid-19 in the Republic, the health authorities said on Saturday.
A further 248 cases were confirmed.
Dr Holohan said: "Ireland currently has the lowest incidence in Europe and has protected against the significant mortality and severe illness that many European countries, as well as the United States, have experienced.
"Our younger generation led the way, with the incidence in the 19-24 year age group reduced from 432 per 100,000 population to 41 per 100,000 population.
"This is an enormous achievement.
"We all need to recognise how well our younger generation has reduced their contacts and helped to protect the whole population."
He said we all now need to follow this example in the weeks ahead.
He added: "We can do this by planning from now for Christmas to reduce our social contacts and limit our activities to those that are essential and most important to us."
Of the cases notified today;
- 124 are men / 122 are women
- 67% are under 45 years of age
- The median age is 33 years old
- 99 in Dublin, 21 in Louth, 16 in Limerick,15 in Meath, 13 in Cavan and the remaining 83 cases are spread across 20 other counties.
As of 2pm today 185 COVID-19 patients are hospitalised, of which 31 are in ICU. 10 additional hospitalisations in the past 24 hours.
