Britain faces the prospect of thousands of annual Covid deaths for years to come, scientists have warned.

They say waves of cases are likely to sweep the country every winter as Covid-19 joins other seasonal viruses, including influenza, in taking its toll of elderly and infirm people. Every year, as cold weather forces people indoors, virus transmission will increase, case numbers will rise, and some of these will result in deaths.

The warning comes as Covid case numbers look likely to stabilise through the summer, but with researchers saying incidence could rise again in autumn as vaccination rates falter and schools return. This could lead to a fourth wave this winter – one that could become an annual occurrence for years to come.

“We are going to see problems with Covid for a long time,” said Prof Adam Finn of Bristol University. “The virus has shown itself to be genetically more nimble than we expected, though not as much as the influenza virus. So I would envisage Covid being a continuing problem for some time, with annual death tolls reaching thousands and possibly tens of thousands.”

This view was backed by Prof James Naismith, director of the Rosalind Franklin Institute in Oxford. “We won’t see Covid-19 spread like wildfire again. There will be enough herd immunity in the population to ensure it will never kick off like that again.

“But everything will not be hunky dory. We will have waves of illness similar to flu, I think. And they will kill. The issue is: how many? That is difficult to assess but if you look at current Covid deaths, these are occurring at about 100 a day.

“So a wave that kills a few thousand seems a reasonable measure of what you might expect in a future winter wave. And then, you might get a bad wave one year and have the tens of thousands of deaths.”

However, Prof Jonathan Ball of Nottingham University said: “I suspect numbers of Covid deaths will decrease over time as population immunity to the disease not only increases but also broadens. This is not to say we won’t have deaths every year. But to say it’s likely to be in the thousands is overly pessimistic.

“It could be to start with, but I think the amount of severe disease will decrease over time because of continual exposure to the virus, which will therefore boost natural immunity.”

Most of those who will die will probably be the old and the seriously ill – the same set of people who have succumbed every winter to influenza and other respiratory diseases. It remains to be seen if Covid-19 will increase average fatality numbers or merely act as a new addition to the repertoire of illnesses that kill vulnerable people every year.

“Covid is not going to be something that brings society to a halt,” added Finn. “And we can minimise the problems it poses – through careful use of vaccines, for example.”

A similar note of caution was expressed by Prof Martin Hibberd of the London School of Hygiene and Tropical Medicine. “I think we may be at a turning point in Covid-19 in the UK, with the proportion of people with antibodies now rising above 90%. That means that soon we will be in as good a place as possible with vaccine protection – and yet, we are still seeing disease.

“This is what we will have to live with: a new nasty disease that will continue to cause problems. I think we can use influenza as an example here. We have vaccines for influenza and yet we still have perhaps an average of 20,000 deaths a year in the UK.”

The prospect of the next Covid wave beginning in autumn, as schools return and the weather worsens, has led scientists to press for the introduction of booster vaccines for people over 50 and for 16- and 17-year-olds to be considered for vaccination.

There is also a fear that previous lockdowns may have weakened the British population’s immunity to other respiratory illnesses such as flu. These worries were highlighted last month by the Academy of Medical Sciences in its report Covid-19: Preparing for the future.

“We are going to go into this winter and start mixing again in ways that we didn’t do last year,” said Dame Anne Johnson, president of the academy. “In those circumstances, we can expect to see a real upsurge in respiratory infections such as flu, for which we may have waning immunity because we were not exposed to it last year.”