Yes, there will be a drop in flu deaths this year for example. And a rebound next year
Air quality has already been reported to be improving. You have 70-90% decrease in plane and vehicle traffic. Less boat traffic too, so water quality will improve. The earth is healing itself. ;-)
Like other diseases? I don't know what this question is asking
Yes other diseases. Sorry for not being clear. I've had trouble with the number of characters limit.