So the question is what has caused increased deaths if there actually was an unusual increase compared to previous years at all? Was it something else, like a multiresistent hospital infection in nursing homes?
> Conclusions: SARS-CoV-2 infection was already circulating in Milan at the outbreak start.
It just means that the virus entered the region a few weeks or months earlier than thought so far (the study started on Feb-24), not that there have been COVID-19 waves in previous years.
This seems similar to the recent news that the first case in France was backtracked to December 2019, e.g. the virus was already spreading before the first cases were discovered:
I think it has more to do with the route of entry of the virus in the territory, which hit hospitals first (not closing down Alzano Lombardo was a grave mistake), then retirement homes (an error shared with Lazio and elsewhere).
This meant that the newly-infected population was largely skewed towards the most vulnerable, and coupled with imperfect knowledge about treatment, the net result was a lot of deaths.
That said, I do think the numbers of the Policlinico study might well be representative, at least regarding Milano. It is just anecdotal, but I know a lot of people there that got sick, but where unable to get tested, or waited weeks before receiving any treatment.
Unless, of course, the antibody test is too general, and is picking up false positives, or antibodies that have nothing to do with COVID.
Just one example here: https://www.theguardian.com/world/2020/apr/09/uk-government-...