Do we actually want this, truely? If the species goes long enough in such sterile environs, free from voracious infection and without the constant assault upon the immune system, wouldn't the ultimate end result be far more disastrous? If removed from our protective civilization bubble or should a disease come along that can penetrate it, couldn't this be far more devastating to a population? Isn't a constant assault from the maximum amount of weakened and lesser disease of paramount importance to a robust and healthy immune response?
I don't think we'd accomplish a truly sterile environment. Even the places with good ventilation and far-UVC light won't be truly sterile. If someone coughs right at you, you are sor gonna get exposed. There will also still be plenty of places where we won't do these things. Most people won't have this in private homes for example. I think it would bring urban areas maybe somewhat closer in exposure levels to what you have in more rural areas.
