There was a past thread on other viruses' behaviour impacted by Covid but is long locked, but there maybe some relevance here: Dr Susan Hopkins says we must prepare for a 'hard winter' of flu, citing reduced immunity to them given their almost non-existence this year:
The population immunity to viruses other than Covid could be lower than usual, a top medic warns.
www.bbc.co.uk
While it's not certain I can certainly see how this is possible, and should really throw in question whether the long term pain of lockdowns is not just limited to economic damage and ignoring things like mental health and cancer, where here other viruses that Covid shut out "learn" to be more infectious to be in with a fighting chance once again.
Regardless of what if any restrictions are necessary though, I'm sure there is almost universal acceptance our health service must be ramped up as quickly as possible to cope, as well as issuing as many flu vaccines (and maybe covid boosters at the same time) as possible. I know staff take a long time to train, but that doesn't mean we shouldn't do it, and the last year should have seen more staff complete education already ongoing, with more in the following year. We need to make sure more training capacity exists and pay and conditions are good enough to retain existing staff too.