Perhaps not directly related but I recall an article that suggested that sunlight and fresh air were the best things for people during the 1918 pandemic. And an increase in vitamin D was specifically mentioned.
Of course, not being in a closed in Victorian era sanitorium with a bunch of other sick people was probably a good thing too.
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells