A member of the government’s Sage scientific advisory committee, John Edmunds, said that the removal of restrictions in England on 19 July will delay the moment at which the wave reaches its peak and starts to subside.
And former health secretary Jeremy Hunt warned that the government must be ready to “change direction” and bring back curbs to social and economic life if infections continue at record rates of 100,000 a day or more.
Warning lights on the NHS are already “flashing red” with Covid hospital patients doubling every two weeks and predicted to reach 10,000 by the end of August, at a time when the service is struggling to make a dent in the massive backlog of patients awaiting treatment for other conditions, Mr Hunt told the BBC Radio 4 Today programme.
If infections remain high as schools return in September, the government will have to “reconsider some very difficult decisions” about restoring restrictions, he said.
His comments came after chief medical officer Chris Whitty warned that England “could get into trouble again surprisingly fast”, with the potential for a “scary” rise in hospitalisations.
With daily infections already above 50,000 two days before step 4 of Mr Johnson’s roadmap out of lockdown, epidemiologist Edmunds told Today that within the next two weeks numbers can be expected to hit 100,000 – well above the record peak reached in January.
The absence of lockdown curbs means that, rather than the relatively rapid decline in infections seen after previous peaks, the UK is facing a “higher level of incidence for a protracted period right through the summer and probably through much of the autumn,” warned Prof Edmunds, of the London School of Hygiene & Tropical Medicine.
“We didn’t ease up restrictions after having vaccinated everybody,” he said. “We did it the other way – we started easing restrictions before everybody was vaccinated.
“That’s going to lead to infections in the unvaccinated people, primarily younger individuals. It’s inevitable that that was going to happen.”
Mr Hunt said: “The warning light on the NHS dashboard is not flashing amber, it’s flashing red. Covid hospital patients are doubling every two weeks and, according to the Health Service Journal, that means that we are heading for about 10,000 Covid hospital patients by the end of August, which is about 20 times higher than this time last year.
“And on top of that, of course, you’ve got the Covid backlog where, for the first time in two decades, we’re seeing lots of people waiting two years for operations. So it’s a very serious situation.”
The experience of countries like the Netherlands and Israel, which lifted restrictions after successful vaccination campaigns but are now considering returning to lockdown amid rising case rates, made clear that the onus is on the public to use its new freedoms responsibly over the coming weeks, said Mr Hunt.
“If we behave like they have done and change our behaviour too dramatically when the restrictions are changed, then we are going to end up having to do what they are doing now, which is reconsider reimposing restrictions,” said the Commons Health Committee chair. “So a lot depends on our behaviour over the next couple of weeks.”
There was little prospect of the reversal of moves out of lockdown during August, because transmission will naturally be limited by the fact that schools are closed and people will spend much of the time outdoors, he said.
But he added: “Coming into September we’re almost certainly going to see infections reach a new daily peak going above the 68,000 daily level which was the previous record in January.
“It will depend on what they’re doing when we come towards the end of the month. If they start to tail off and go down again then we hopefully can stay on the current trajectory.” but if they’re still going up as the schools are coming back, then I think we are going to have to reconsider some very difficult decisions.”
Mr Hunt said the “herd immunity” offered by vaccinations and previous infections made him “hopeful” that a new lockdown can be avoided. But he added: “There is a lot of uncertainty, which is why it’s very important that the government is willing to change direction if that’s what the data says we have to do.”
Meanwhile, a senior union official accused the government of approaching the reopening of the economy “through the prism of politics, rather than pragmatic common sense action”.
Paul Nowak, deputy general secretary of the TUC, told BBC Breakfast: “What we’ve seen is strong workplace guidance – that unions and employers helped shape – that’s kept millions of people safe during the course of last year, replaced by vague exhortations, recommendations, guidelines.
“I think it poses more questions for employers than it provides answers.”