The German economist Andreas Wagner tells BBC Radio 4's Today program that people are twice as likely to cough during concerts of classical music than they are outside the concert hall. That holds true, Wagner says, even when the relatively older age of classical audiences is taken into account, reports Rosa Silverman of The Telegraph (UK):
http://www.telegraph.co.uk/culture/music/classicalmusic/9833586/Coughing-in-classical-concerts-twice-as-likely.html
And when can one expect crescendos of coughing? In modern works and slow movements.
If that surprises you, sneeze.