Sometimes people talk like it's obvious to everyone that the #flu is airborne, but I have never seen -- in a pretty liberal area of the US -- a doctor in a respirator mask during flu season in my life (and I'm 32)
A 2013 study using non-respirator surgical masks -- so this is likely an underestimate -- still found that half out of 782 #influenza A transmissions in Hong Kong and Bangkok households happened this way: