The Chief Medical Officer is encouraging all people who are eligible for vaccination but have not yet been vaccinated to do so "as soon as they can".
Dr Tony Holohan said that "full vaccination is the best protection" against Covid-19, including from strains such as the Delta variant.
“It is important to remember that infections in vaccinated people do not mean that vaccines do not work," he said.
"While no vaccine is 100% effective in this way, these breakthrough infections that occur are generally much less severe, and they are associated with less risk of hospitalisation.
Dr Holohan's comments come as the Department of Health has been notified of a further 1,314 cases of Covid-19.
The number of people with the disease in the hospital is 187, with 30 of them being treated in intensive care.
There has been a total of 5,044 deaths related to Covid-19 in the State since the beginning of the pandemic.
In Northern Ireland, an additional 1,040 cases of the virus have been confirmed and one further death.
There are 226 people in hospital with Covid-19, 38 of whom are in intensive care.
The US Centers for Disease Control and Prevention (CDC) has said travel to Ireland from the US should be avoided, even if fully vaccinated.
The CDC issued the recommendation which states that because of the current situation in Ireland, "even fully vaccinated travellers may be at risk of getting and spreading Covid-19 variants".
The European Commission has approved an advance purchase agreement for a Covid vaccine that is currently under rolling review.
Under the contract, member states will be able to buy up to 100 million doses of the Novavax vaccine, with an option for an additional 100 million doses over three years.
The deal comes into effect when the European Medicines Agency (EMA) reviews and approves the vaccine as safe and effective.
Commenting on the news, European Commission President Ursula von der Leyen said: "As new coronavirus variants are spreading in Europe and around the world, this new contract with a company that is already testing its vaccine successfully against these variants is an additional safeguard for the protection of our population."
The deal would allow EU states to receive the first Novavax doses from the last quarter of this year.
The Novavax vaccine uses different technology to the vaccines currently in use across the European Union (EU) and European Economic Area (EEA).
The vaccine was developed using protein-based, subunit technology.
Reducing the gap between vaccine doses may be considered to fight the Delta variant, the EMA and the European Centre for Disease Prevention and Control (ECDC) has advised.
In a statement, the groups said it may be advisable to consider reducing the interval between first and second doses, within the authorised limits, particularly for people at risk of severe COVID-19 who have not completed the recommended vaccine schedule.
The groups also advised that although the effectiveness of all Covid-19 vaccines authorised in the EU/EEA is very high, no vaccine is 100% effective.
This means that a “limited number” of so-called breakthrough infections (Covid-19 infections among persons that are fully vaccinated) are expected.
However, when infections do occur, vaccines can prevent severe disease to a large extent, and greatly reduce the number of people in hospital due to the virus.
Fergus Sweeney, EMA’s Head of Clinical Studies and Manufacturing said; "As long as the virus continues to circulate, we will continue to see breakthrough infections in vaccinated people.
“This does not mean that the vaccines are not working.
“Vaccinated people are far better protected against severe COVID-19 than unvaccinated people, and we should all endeavour to be fully vaccinated at the earliest opportunity.”
The EMA and ECDC continue to recommend full Covid-19 vaccination for all eligible citizens.