Prof Mark Harris, of the School of Molecular and Cellular Biology at the university, said, while he can see the economic reasons behind wanting lift restrictions, the decision is “not based on science”.
Prime Minister Boris Johnson announced on Monday night that the final restrictions will end in England on Thursday and the free mass testing will stop from April 1.
But Prof Harris told the Yorkshire Evening Post: “I have a level of concern for how things are going to pan out.
“We know that people will be infectious after they test positive.
“If they are allowed to then go out into the community, into workplaces, into busy restaurants, even though they are positive, they will potentially transmit the virus. And the worry is that they will do [just] that, because they will go into an environment where people are not socially distancing, not wearing masks.”
He said this puts those who are clinically vulnerable and those that are unvaccinated at particular risk.
“There will be consequences. We will see an increase in the numbers of people infected. But if you stop testing, we won’t even know that - we won’t be measuring. We’re kind of saying ‘just deal with it, we’re not going to even consider how many people are going to be infected’.
He said: “I’m concerned for the future. I would say personally, I feel less safe,” adding: “Just not knowing what environment I’m going into.”
With more infections, he said, comes the increased likelihood of new variants, such as the current Omicron subvariant BA.2, which he said little is still known about.
“Things are changing already from where we were with Omicron before Christmas.”
To those who believe we need to live with Covid, like we do with the flu, he said: “I can see that after two years of pandemic, people are just kind of fed up.
“But this is not the flu. Boris said [in his announcement] that there [fewer than] 10,000 people in hospital. And I thought that was an extraordinary statement. There are not ‘only 10,000 people’.
“There are 10,000 people in our hospitals who are seriously ill with Covid - so ill they have had to be taken into hospital to be given oxygen or looked after. This is not like flu. We don't have 10,000 people in hospital with flu.”
Prof Harris said: “Yes we can live with it but the consequences are there will be more infections, people will get seriously ill, we don’t yet know the long-term consequences of the virus, in terms of Long Covid we’re still learning about that. These are risks that we can avoid by taking just a little bit more precautions.”
He argued, for example, if social isolation is being removed, it would be sensible to still have mask wearing, so as to prevent transmission.
“[Yet] we are kind of removing everything and saying ‘it doesn’t matter if you're infected and if you’re infected it doesn’t matter about transmission to other people'.”
Boris Johnson set out the Government's strategy for "living with Covid" on Monday as he hailed the development of vaccines and treatments for coronavirus as "possibly the greatest national effort in our peacetime history".
But the Prime Minister said "we should be clear that the pandemic is not over", warning "there may be significant resurgences".
Professor Sir Chris Whitty, England's chief medical officer, said the Omicron wave is "still high", adding that new variants are anticipated, with some expected to "just disappear", while others will cause "significant problems".
Mr Johnson acknowledged there will likely be another variant that will "cause us trouble", saying he did not want people to think "there's some division between the gung ho politicians and the cautious, anxious scientists".
He said: "The most important thing is that - and I hope this is the big take out from this... the sun is shining but we're keeping our umbrella."