The UK could open up "sooner rather than later" thanks to the huge numbers of people being vaccinated - and the country is not experiencing a third wave of infections, a vaccine expert has told Sky News.
Brendan Wren, professor of vaccinology at the London School of Hygiene and Tropical Medicine, said that having more than 81% of the adult population with a first coronavirus jab, and 59% with both doses is "very encouraging".
Asked whether the success of the vaccine programme means England will not need to wait until 19 July to fully open up, he said: "We'd still need to be vigilant - but vigilance and vaccination are the two words.
"So, I think if the numbers continue to be promising then I think there's great hope we could open up on 5 July."
However scientists have warned an emergence of new respiratory viruses means a "pretty miserable winter" is ahead for the UK, with further lockdowns a possibility.
Professor Calum Semple, member of the Scientific Advisory Group for Emergencies (SAGE), which advises the government, has said that children and elderly people will be vulnerable to endemic viruses at the end of the year.
Calling it the "fourth wave winter", he told Times Radio "there's a sting in the tail after every pandemic" because social distancing will have reduced people's exposure to usual endemic respiratory viruses such as pneumonia and bronchiolitis.
"I suspect we'll have a pretty miserable winter because the other respiratory viruses are going to come back and bite us quite hard," he said. "But after that, I think we'll be seeing business as normal next year."
Meanwhile, Dr Susan Hopkins, Public Health England's director for COVID-19, warned "we may have to do further lockdowns this winter" depending on whether hospitals start to become overwhelmed.
But she told the BBC's Andrew Marr Show: "I think we will have alternative ways to manage this, through vaccination, through anti-virals, through drugs, through testing that we didn't have last winter."
All of England's lockdown restrictions were due to be lifted tomorrow but Boris Johnson announced a four-week delay amid rising cases of the Delta variant of COVID-19.
The remaining restrictions are now expected to be scrapped on 19 July but the prime minister has said a review will take place to see if action can be taken two weeks sooner on 5 July.
Official figures show the UK has recorded more than 10,000 daily COVID cases for three consecutive days.
But Prof Wren explained that the rise in cases seems to be "flattening off", saying: "If you are testing and tracing more, then you are going to find more cases... but if you look at the population as a general cross-section, then the actual numbers - proportion-wise - might be less."
The expert said the number of people in hospital with COVID and "certainly the severe cases" have "not crept up in line" with the number of infections.
"There's clear evidence here that the vaccinations - certainly in the older populations - are working," he added.
"Although the number of cases may increase, the number of hospitalisations, or deaths, or expected deaths, is not increasing in line with the previous waves."
And asked whether the UK is experiencing a third wave of the pandemic, Prof Wren said: "I don't think particularly. We expected that there would be an increase as we gradually opened up but I wouldn't call this a third wave.
"The numbers aren't as great and given that such a huge proportion of the population are protected, then it's unlikely to go up and I'd also say that I think the population are more educated.
"We have better testing and tracing, so I don't expect that we're going to have a huge peak like we've had in January and last year."
Prof Wren said it was "very encouraging" that more than 700,000 vaccine appointments were booked on the day that jabs became available to people aged 18 to 20 in England.
He added that the high proportion of UK adults who have been jabbed "will mean we will be able to open up sooner rather than later".
Watch: COVID-19 - Remaining restrictions in England 'unlikely' to be lifted early on 5 July - minister