Professor Calum Semple, member of the Scientific Advisory Group for Emergencies (Sage), which advises the Government, has said that children and elderly people will be vulnerable to endemic viruses at the end of the year.
Another health expert and Government advisor warned that there may be the need for winter lockdowns if hospitals become "overwhelmed" at some point.
On Sunday morning, Professor Semple told Times Radio: "I suspect we'll have a pretty miserable winter because the other respiratory viruses are going to come back and bite us quite hard. But after that, I think we'll be seeing business as normal next year.
"There's a sting in the tail after every pandemic, because social distancing will have reduced exposure, particularly of pregnant women and their newborn babies, they will have not been exposed to the usual endemic respiratory viruses.
"The protection that a pregnant woman would give to their unborn child has not occurred.
"So we are going to see a rise in a disease called bronchiolitis, and a rise in community acquired pneumonia in children and in the frail elderly, to the other respiratory viruses for which we don't have vaccines.
"So that's why we're predicting a rough July, August and then a rough winter period."
Professor Semple called it the "fourth wave winter" but added it would be much milder than the previous ones.
Dr Susan Hopkins, the strategic response director for Covid-19 at Public Health England (PHE) also warned of a possible rise in cases at the end of the year.
She told the BBC's The Andrew Marr Show: "We may have to do further lockdowns this winter, I can't predict the future, it really depends on whether the hospitals start to become overwhelmed at some point.
"But I think we will have alternative ways to manage this, through vaccination, through anti-virals, through drugs, through testing that we didn't have last winter.
"All of those things allow us different approaches rather than restrictions on livelihoods that will move us forward into the next phase of learning to live with this as an endemic that happens as part of the respiratory viruses."