Coronavirus will still be with us for decades even if we have a vaccine, experts have warned.
Prof Sir Jeremy Farrar, director of the Wellcome Trust, told the Commons health and social care committee on Tuesday: "Things will not be done by Christmas. This infection is not going away, it's now a human endemic infection.”
The top scientist, a member of the Government’s Sage advisory committee, added: "Even, actually, if we have a vaccine or very good treatments, humanity will still be living with this virus for very many, many years.... decades to come."
The stark forecast is a blow for Prime Minister Boris Johnson, who said last week that he hoped for a “significant return to normality” by Christmas.
Lockdown is set to be eased again on August 1 to allow most remaining leisure venues to reopen, including indoor swimming pools, theatres, bowling alleys and beauty salons, and to encourage employers to reopen offices.
But Sir Jeremy warned against easing the curbs too quickly, insisting the summer was a “crucial phase” to reduce the chance of a second spike.
"If we have any sense of complacency of 'this is behind us', then we will undoubtedly have a second wave, and we could easily be in the same situation again,” he said.
The warning was echoed by Prof Sir John Bell, an immunologist from the University of Oxford, who said the pathogen behind Covid-19 will never be fully defeated.
"The reality is that this pathogen is here forever, it isn't going anywhere," he told MPs.
"Look at how much trouble they've had in eliminating, for example, polio, that eradication programme has been going on for 15 years and they're still not there.
"So this is going to come and go, and we're going to get winters where we get a lot of this virus back in action.”
He said a “continual cycle of vaccinations, and then more disease, and more vaccinations and more disease” would last for decades.
“I think the idea that we're going to eliminate it across the population, that's just not realistic,” he told MPs.
The comments came hours after Oxford scientists revealed they had successfully completed the second phase of developing a Covid-19 vaccine.
Details of the Oxford University vaccine phase 1/2 trial involving 1,077 healthy adults found that it induced strong antibody and T cell immune responses for up to day 56 of the on-going trial, results published in The Lancet showed.
Ministers have already ordered 100 million doses of the vaccine from AstraZeneca, which is working with Oxford University, to be rushed out in the UK if it gets the all-clear.
Meanwhile, Prof Chris Whitty, England's chief medical officer, launched a staunch defence of the Government waiting until March 23 to lock down Britain, saying it was not a "huge" delay.