The NHS has been warned to brace for a particularly deadly flu season with as many as 60,000 deaths this winter.
Scientists have warned that a combination of seasonal viruses and Covid could mean that the NHS is "unable to cope" this winter.
A new report warned that a mix of coronavirus, flu and respiratory syncytial virus (RSV), could put severe strain on the NHS this winter.
Scientists said that people who are sick should "stay out of the way" to avoid spreading flu and other winter viruses and stop the annual pressure put on the NHS.
The new report from the Academy of Medical Sciences says there is still high levels of uncertainty around the effect flu and other respiratory illness could have on the NHS over the winter.
It is feared that flu and RSV hospital admissions and deaths could be twice that seen in a "normal" year and could coincide with an increase in Covid infections.
Models suggest between 15,000 and 60,000 could die from flu this winter.
And due to the current wave of infections the NHS could face difficulties trying to catch up on the backlog of care - with more than 5 million people in England on the waiting list.
The report highlights other problems that the health service faces going into winter including staff shortages and reduced bed capacity.
But experts said steps can be taken to reduce the risks, including the widespread flu campaign which is expected to take place later this year for over 50s.
They also called for the expansion of Covid testing to also include tests for flu and RSV.
More must be done to support people who self isolate and the NHS needs a "boost" of staff, bed numbers and capacity, the authors said.
Meanwhile they called on the Government to give more accessible guidelines about the precautions the public can take to protect themselves and those around them from Covid-19, such as wearing face coverings in crowded indoor spaces, physical distancing and minimising transmission when infected.
Professor Sir Stephen Holgate, chair of the Expert Advisory Group which wrote the report, said: "There are four main challenges: firstly a surge in respiratory viruses could cause wide-spread ill health and put pressure on the NHS.
"Secondly, we're dealing with a third wave of Covid-19 and multiple outbreaks and the NHS has got to catch up with the backlog that it has accumulated over the last 15 months or so, and that's going to be a real challenge.
"Thirdly, the NHS is already under pressure, so is likely not to be able to cope with these winter challenges going forward.
"Finally the worse physical and mental health health within the UK population due to the pandemic."
Professor Dame Anne Johnson, president of the Academy of Medical Sciences and Expert Advisory Group member, added: "We're not saying we're about to have the worst winter ever, we're saying we have got a bunch of uncertain things that could hit us in winter that we need to think about mitigating now."
She added: "I hope we will take forward some of these behavioural changes as a society. When you're sick, stay out of the way because that's actually when you're most infectious, get your test - if you have got Covid you need to continue with that careful self isolation."
An NHS spokesperson said: "NHS staff have worked tirelessly throughout the pandemic responding to increased demand by expanding critical care capacity by 50% in hospitals, managing admissions through mutual aid and working with the independent sector.
"And ahead of winter, the NHS will continue with tried and tested plans to support hospitals so that they can continue to offer patients the care they need while restoring routine operations back to pre-pandemic levels and vaccinating the country against Covid."
