Dr Tony Holohan, Chief Medical Officer, said: "It is concerning to see the rising number of people with Covid-19 in hospital.
"This means that our collective efforts to follow the public health advice remain very important."
He added: "I know that many have sacrificed valuable time with friends and family to protect themselves and the wider community. These continued efforts are helping to slow the spread of this virus and will protect many from infection in the next few weeks.
"The Covid-19 vaccine booster will protect the majority of people from severe disease.
"The booster programme is now open to everyone aged 16 and over. If you are not yet fully vaccinated or are yet to receive a booster dose, please take this opportunity to protect yourself as soon as possible."
Dr Holohan also urged people to "isolate immediately if symptomatic, keep your social contacts as low as possible, avoid high risk activities and poorly ventilated environments".
