Chief Medical Officer Dr Tony Holohan has said that the trajectory of Covid-19 in Ireland 'remains uncertain' as the country struggles to stem the spread of the Delta and Omicron variants.
The news comes after the Department of Health reported a further 5,590 new cases on Tuesday, with 505 people being treated in hospital, 117 of whom are in ICU.
In a statement, Dr Holohan urged people to get the booster vaccine after reports of thousands of people not turning up to appointments.
He said: "The current high incidence of Covid-19 that Ireland is experiencing is driven by the Delta variant, which, coupled with the presence of the Omicron variant, means that the trajectory of the disease remains uncertain.
"Booster vaccinations have been shown to produce very strong antibody responses and are likely to provide protection against severe disease, hospitalisation and death from most variants, including Delta and Omicron, at least in the short term.
"In the over 75 age group, where people have been taking up the offer of a third dose of a Covid-19 vaccine in high numbers, we are seeing significant reductions in the incidence of disease.
"This is another positive development and further evidence that getting a third dose of Covid-19 vaccine helps to protect from the most severe effects of Covid-19.
"Do not wait until after Christmas to receive your booster vaccine, the benefits of receiving your booster dose far outweigh any potential risks that may arise in the meantime."
Dr Holohan said the benefits of receiving the booster jab would be seen within seven days, allowing people to feel more confident over the festive period.
He said: "You will begin to receive the benefit of your booster protecting with seven days of receiving your third dose. This means that anybody who received their vaccine this week can be confident in the protection the booster will offer them as we move closer to the Christmas period."
As the Delta variant remains the dominating strain of Covid in Ireland, worry has grown that the new Omicron variant will add huge pressures to the already strained health system.
However, new information from the World Health Organisation suggests that the vaccines will be somewhat effective against the Omicron variant. The strain may also cause less severity of illness than Delta.
The Omicron variant is currently believed to be more transmissible than other strains, but the WHO has said it is "highly unlikely" vaccines will be ineffective on the variant.
WHO emergencies director Michael Ryan said in an interview: "The preliminary data doesn't indicate that this is more severe. In fact, if anything, the direction is towards less severity."
However, Dr Ryan emphasised that more research was needed before any definitive conclusion could be drawn.
He added: "We have highly effective vaccines that have proved effective against all the variants so far, in terms of severe disease and hospitalisation ... there's no reason to expect that it wouldn't be so."
