The UK will be living with coronavirus for many years to come and even a vaccine is unlikely to eliminate it for good, experts are warning.
Wellcome Trust director Prof Sir Jeremy Farrar told the House of Commons' Health Committee "things will not be done by Christmas".
He went on to say humanity would be living with the virus for "decades".
It comes after the prime minister said last week he hoped for a return to normality by Christmas.
Vaccine 'unlikely to have durable effect'
Prof Sir John Bell, of the University of Oxford, said he thought it was unlikely that Covid-19 would ever be eliminated despite the positive news announced on Monday that trials by his university had triggered an immune response - an important step in developing a vaccine.
"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.