Thats mad. The population has had general immunity from flu for decades, cos our immune system knows it and deals with it. Man flu notwithstanding. They just give booster jabs to protect the age group at risk from the latest one.
I think it's a bit of a misquote: it suspects that flu will be worse than COVID this
upcoming winter due to reduced immunity and a number of other factors.
With a population that has had mass immunisation against COVID, its likely that flu will cause more deaths due to a lower immunisation rate in general.*
A bad flu season can cause significant deaths, so any reduced immunity that will have been created through the circumstances could have an impact.
However, it's certainly not going to be worse than COVID in the general sense e.g. worse than the past eighteen months; still, it could be a bad flu season.
Yet, I hope it's not as I think we all need some optimism and the NHS certainly needs a breather, but I do know it's something they'll plan for as a contingency.
*It's around the 75% mark for over 65s, with the wider population much lower.