People who are still unvaccinated should not try to slip in “the back door” of the pub or to holiday abroad amid fears the country is at the start of another dangerous Covid-19 wave, with a difficult 10 weeks ahead, chief medical officer Dr Tony Holohan has warned.

Parents should also not bring their children into a pub or restaurant but instead dine outside, he added.

There are higher rates of infection already among 13- to 18-year-olds.

Expectations for hundreds of thousands of people were dampened as he signalled a two-tier summer with the fully vaccinated – who make up just 58pc of adults – free to avail of pubs, restaurants and European travel.

But the unvaccinated, who are most at risk from the highly infectious Delta variant, need to hold out until they are protected, which is “not far away”.

He said “we have two messages”, and for the most part the fully vaccinated can regard themselves as being able to take part in activities now “open and available” – although if they have respiratory symptoms they should not be mixing.

He told those waiting for a vaccine to, at the very minimum, try to differentiate for themselves those activities that are high risk.

He said “your vaccine is not far away” and “it will take us into September”.

However, he warned that the next 10 weeks will be “very uncertain”.

He was speaking as 783 new cases of the virus were reported yesterday. There was an increase in hospitalisations, with 73 patients with Covid-19 in hospital, of whom 20 are in intensive care.

Government legislation on indoor hospitality, which passed a Dáil vote last night, allows fully vaccinated parents to bring their children into a restaurant or pub.

However Dr Holohan said: “You don’t have to go indoors. We know Delta transmission among children can happen.”

There were 12 virus-related deaths in June and one to date in July.

Professor Philip Nolan said the growth in incidence of the more contagious form of Covid-19 is strongly linked to unvaccinated people.

The highest rate is seen in 19- to 24-year-olds, followed by 13- to 18-year-olds and 25- to 34-year-olds.

It is still unclear how an escalation in spread will affect hospitalisations and deaths.

But he said: “Where we typically had two admissions every five days to intensive care, we are now looking at an average of one admission per day. Where this is going into the future isn’t entirely clear.”

The virus is growing by around 3.5pc a day. “The growth rate now is similar to or perhaps slightly less than the growth rates we saw through August, September and October of last year, but starting from a higher base.”

The trajectory is now veering towards some of the more pessimistic forecasts which could see 1,750 Covid-related deaths over the rest of July, August and September.

The modelling took into account the accelerated roll-out of vaccines and estimated it would spare around 30,000 people getting infected in August and September.

The worst hit areas are Buncrana and Carndonagh in Co Donegal, followed by Limerick city north, Ongar in west Dublin and Ardee in Co Louth.

Deputy chief medical officer Dr Ronan Glynn said nearly one in 10 cases in the last two weeks were travel-related, with Spain, Britain and Portugal among the countries people who were positive had returned from.