I doubt that there would have been so many cases of death that statistics would have been distorted alarmingly. Also, they didn't know what they might be looking for then, and in most cases I presume they would have recorded known conditions?
Agreed - but if so why no rise in Pneumonia deaths ahead of the covid curve we see now?
A few factors can somewhat explain this; the degree to which vulnerable people are naturally, relatively sheltered from infection, and the case mortality rate.
This is something I find very interesting. I can well imagine that the date of when it was 'here' may end up getting pushed back even further.