It is “inevitable” there will be a surge in coronavirus cases when schools reopen after the summer break, an infectious disease expert has said.

Paul Hunter, professor in medicine at the University of East Anglia, warned that a rise in transmission when students go back to school in Norfolk on September 6 would see a jump in positive cases.

“Infection rates will increase once schools are back, certainly after the first two weeks,” he said.

“The issue is how much that translates into severe disease and hospitalisations. That is the big uncertainty at the moment.”

Deaths from Covid-19 across the UK are at the highest for over five months, according to official data, and scientists have warned that case rates will jump again when millions of pupils return to schools in 10 days time.

The seven-day average for deaths within 28 days of a positive test now stands at 100, figures released by Public Health England on Monday show, a number that was last exceeded on March 18.

Cases in Scotland, where schools went back last Monday, more than doubled on Friday compared to the same day a week earlier – from 1,542 to 3,613.

While that rise cannot be solely linked to the start of the new school term just four days earlier, it is being seen as a contributing factor.

Prof Hunter said a rise in infections may not mirror the significant increase seen after schools returned last September.

“Some people are pointing to what happened last autumn but it is not going to happen like that this time, partly because of the vaccine but also because a lot of people are still immune from having had the infection and recovering,” he said.

“So it’s a bit uncertain what will happen. I suspect case numbers will go up and hospitalisations will increase but probably not as dramatically as we saw last year.”

His comments come after the government launched a campaign to drive uptake of the Covid vaccine among 16- and 17-year-olds.

Secondary schools in Norfolk face a staggered start to the new term as they Covid test hundreds of pupils twice three and five days apart.

The Department for Education has also updated its advice for schools and colleges on how serious Covid outbreaks need to be before they send pupils home or close classes.