Covid-19 is unlikely ever to be eradicated and the outlook for the pandemic remains “pretty bleak” in the medium term, leading Government scientists have said.

England’s chief medical officer Professor Chris Whitty said the world will continue to see a “significant” number of deaths unless more effort is made to vaccinate the vulnerable globally.

And he warned that while coronavirus may become a “much milder, chronic disease” in the long term, new variants will continue to cause problems.

Speaking at a Royal Society online event about Covid-19 on Thursday, Prof Whitty said: “In the medium term, the outlook still looks pretty bleak around the world.

“I would really reiterate that until we have got a situation where we have induced immunity in those who are most vulnerable everywhere in the world, we will continue to see really significant morbidity and mortality from this virus.”

Prof Whitty said that while time and science “was on our side”, the virus was not “going to go away”.

He added: “In the long term I do expect that this will become a much milder, chronic disease overall, probably with seasonal peaks, and from time to time there will be enough of an antigenic shift that actually we have another problem to which we have to respond in due course.”

Professor Wendy Barclay, who is advising the Government’s Covid-19 response, said there was “a lot to do” in the medium term in order to bring the pandemic under control.

She said: “We will not eradicate this virus.

“It is so far spread around the world and the vaccines do not necessarily completely prevent transmission.

“I think we will live with the derivatives of Sars-Cov-2 for a very long time.”

Dr Katrina Lythgoe, from the University of Oxford’s Big Data Institute, said only two viruses have ever been eradicated through vaccination – smallpox and rinderpest.

She said failure to provide poorer countries with vaccines will also result in more potentially resistant variants of the virus “constantly coming at our shores”.

Asked by event host Professor Brian Cox what the consequences would be if the UK took a “single country focused view” around vaccinations, Dr Lythgoe said: “Variants that come in will be a reflection of what’s circulating in the countries people are coming from.

“So of course if there is a lot of virus circulating, and we are seeing, heaven forbid, more variants that we need to worry about, then they will be constantly coming at our shores.

“The greater that flow into our shores, the bigger the probability one of those infections coming in will seed a bigger outbreak.”