Testing to see who has had it will show one thing, and one thing only, many people have had and have got it, precisely why the initial data re mortality rate was skewed. If you had tested every person in the country last year or any other year when we've had bad influenza, you'd find an exceptionally large % of people having had flu and still have it.
Remember large % of those with influenza show no symptoms but are carriers, large % show very mild symptoms but are carriers, all carry on as normal unless they work with very high risk patients. Those with worse symptoms might but not all stay off work for a couple of days until they feel a bit better but are carriers, some of those might even bother to report to a medical professional, they are carriers. If ANY of these people have children they will likely have passed that on to them and anyone else they'll have come into contact with, child shows no symptoms goes to school, passes it on to other kids, teachers TAs, bus drivers etc.
This is why despite the low mortality rate (which in itself by definition of the above is skewed) influenza kills so many in this country and around the globe every single year, influenza is everywhere, this is impossible to eradicate just like C.19, not by self isolation/social distancing and 'lock down'. And by the time a vaccine comes out it will have been and gone, not that a vaccine would eradicate Corona Viruses as a whole in any case as we've seen in the last 60 years and as explained in the video I linked to earlier. the 7-15% that Corona Viruses will be of all respiratory diseases are from the unit in Glasgow that are currently working on this variant right now, they can't be lying can they?
This year might show lower than normal influenza deaths, in fact I would be surprised if it didn't given the extreme extra care being enforced, but this cannot be maintained, it's impossible to maintain, so what happens next year or the year after when influenza and other respiratory diseases and other CVs kill in the tens of thousands and government bother to test everyone for flu (the most virulent and widespread) and see millions of cases every week, not just per year, lock down and social isolate again and again and again indefinitely?
Because if the lives of those dying from C.19 matter than what about those whom have died from influenza not just this year but all the years before, over a quarter of a million influenza deaths in the last 10 years, where was the lockdown to prevent that? What about all the other RD in the past and each and every day going forward, do we not then do same for that, if not, why not?