Ireland still faces a 'very, very real-life threat' from COVID-19 variants, the HSE CEO has warned.
Paul Reid says he appreciates many people need a break, but everyone has to make a "personal risk assessment" when it comes to international travel.
International travel is due to resume from mid-July when the Government implements the EU's digital green cert programme.
The Chief Medical Officer Dr Tony Holohan has urged people not to travel anywhere unless they are fully vaccinated.
However, Tánaiste Leo Varadkar has claimed it would be unfair to tell younger people who haven't been vaccinated yet that they can't travel.
Speaking on Newstalk Breakfast, Mr Reid said this is not a normal summer.
He said: “If you look at what’s happening around the world… the UK has recently announced they’re going to keep the restrictions on overseas travel for now to protect against new variants, and Belgium has banned travel from the UK.
“I appreciate people need a break, but there is a personal risk assessment we all have to make.
“Some of the strongest advice [we gave to Government] was we just can’t let our health system go back to where we were in January. We’re still dealing with a very, very real-life threat from the Delta variant.”
He added that decisions around travel are ultimately a decision for Government.
Meanwhile, the HSE CEO also says people waiting for their second dose of the AstraZeneca COVID-19 vaccine will get one over the next four weeks.
He said those still waiting will hear from the HSE shortly, with second doses to be completed by mid-July.
It comes as the vaccine programme continues to expand, with registration opening to 38-year-old from today.
Mr Reid says the strong momentum will continue for the next few weeks.
He said: “Last week… we had most likely over 340,000 vaccines administered… a really strong week.
“Yesterday, [we had] the announcement of opening vaccines to those aged 39. We had 47,000 registrations already, up to this morning. There’s really strong momentum.
“We will be staying above the 300,000 vaccines per week administered, and rolling out down through the stages for the next three weeks. What then happens in July, is we go back to forecasted levels [of around 200,000 per week], because these three weeks are a function of Pfizer in particular bringing forward deliveries.”
He said around 66% of adults have now had one dose of a vaccine, while around 35% are fully vaccinated.
He expects that around 70% of people will have received at least one dose by the end of July, while there’ll also be a ‘key focus’ on second doses in the coming weeks.
One of the key questions around the rollout is how long people will have to wait for a second dose of the AstraZeneca vaccine.
Officials have decreased the waiting time between doses, but thousands of people in their 50s and 60s are still waiting to hear when they’ll get their second jab.
Mr Reid said: “It will be completed by the week commencing 19th July.
"450,000 people will receive their second dose through the vaccination centres.”
He added that the Johnson & Johnson vaccines being made available through pharmacies are ‘purely’ for people in their 50s who haven’t received any vaccine yet.