Health officials have expressed concern with the number of cases of Covid-19 among under 45s.
In a letter to the Health Minister Stephen Donnelly, NPHET says 73 per cent of confirmed cases from the past 2 weeks have been in that age group.
It also highlights a rise in cases among 25 to 34 year olds.
It's recommended refreshing the government messaging around Covid-19 and targeting younger people.
Action Chief Medical Officer Dr Ronan Glynn says there is no blame being given to younger people, but added the rise in cases in those age groups needs to be highlighted.
Advice from NPHET to the Health Minister also highlighted the 'risk' of social gatherings in private homes, which are described as 'uncontrolled environments'.
The current advice is that no more than 10 visitors from a maximum of 4 different households should gather in a private setting.