I would think on a common sense approach for the reason.
People are wearing masks. Not all of course but most seniors are. That could result in
less flu and pneumonia. Also, people are not out and about as much....here again, especially
the senior population.
Another reason may be due to more people taking vaccination seriously since the pandemic.
Many people that normally would not take the flu shot may be taking it. In regards to
pneumonia vaccine in the USA, one has to be 65 years old at least before they can get it.
The exception is those with particular disease may bet it early.
Another reason is due to the enormous publication, commercials, etc, about the importance
of vaccinations and protecting oneself from the covid.
In regards to heart, stroke, various could be reasons such as unemployed, home more, less
office stress, taking care of oneself more, etc.
Of course, when someone dies such as an old person with many diseases, but dies of covid,
it goes down as covid. If covid is the clincher, then covid it is.