The fast-spreading Omicron variant is "not the same disease we were seeing a year ago" and high Covid death rates in the UK are "now history", according to John Bell, regius professor of medicine at the Oxford University.
Bell, who is also the government's life sciences adviser, said that although hospital admissions had increased in recent weeks as Omicron spreads through the population, the disease "appears to be less severe and many people spend a relatively short time in hospital", reports The Guardian.
Fewer patients were needing high-flow oxygen and the average length of stay was down to three days, he said.
"The horrific scenes that we saw a year ago of intensive care units being full, lots of people dying prematurely, that is now history, in my view, and I think we should be reassured that that's likely to continue," Bell told the BBC.
Several scientists have criticised the government's decision not to introduce further Covid restrictions in England before New Year's Eve, with some describing it as "the greatest divergence between scientific advice and legislation" since the start of the pandemic, the report said.
They have expressed concern that while the Omicron variant appears to be milder, it is highly transmissible, meaning hospital numbers and deaths could rise rapidly without intervention, it added.
The NHS Providers chief executive, Chris Hopson, said it was still unclear what would happen when infection rates in older people started to rise.
"We have had a lot of intergenerational mixing over Christmas, so we all are still waiting to see, are we going to see a significant number of increases in terms of the number of patients coming into the hospital with serious Omicron-related disease," Hopson was quoted as saying by the BBC.