The Medical Director for South West NHS England has told ITV News he fears flu could claim 5 or 6 times as many lives as last year, as people socialise and mix once again.
His warning comes as the NHS is urging those who qualify for the flu jab to take it up immediately.
There are concerns that hospitals across the West Country could be overrun with patients sick with both flu and Covid.
While our region has a high uptake of the flu vaccine, NHS managers want vulnerable people - not just older people - to make sure they get the jab to avoid hospital backlogs this winter.
Dr Michael Marsh said: "It is easy to forget the importance of having flu vaccine for vulnerable members of the public.
"The worry is that because we were in a lockdown last year, the number of flu cases were a lot smaller but as winter comes this year and flu starts to circulate we expect to see many more cases.
"With healthcare services struggling to cope with demand, as a side effect of the pandemic, the worry is that services will be overwhelmed.
"If we have a good flu vaccine uptake there is every reason the believe that we could stop that happening and manage to cope with some flu and continued covid while also doing the recovery work that's necessary from all the delayed treatments over the last 20 months or so."
Christchurch Medical Centre in Downend near Bristol saw people eager for their Covid booster jab.
One patient told ITV News: "I still know family and friends who haven't had the vaccine. You can only advise them and be concerned but it's up to the individual.
"I can only advise them and say please have it done because it's not just yourself, it's also other people that you're putting at risk."
Another said he felt concerned about current pressures on the health service: "They're under immense pressure and unfortunately we have got a lot of non-believers out there which causes even more issues.
"It's a great concern, especially for other people with other illnesses."
Dr Julie Yates from NHS England said: "Flu can be a really serious illness, particularly for people who have other conditions. This is the first year that we will see flu and Covid19 viruses circulating together and we don't know what the impact of that will be.
"It's important that we do minimise the potential impact by doing everything that we can and that includes having vaccinations.
"With high uptake of the flu vaccine we can potentially prevent those people who would otherwise need hospitalising from needing to do that, freeing up the services for other people who need to be cared for."