The flu, like a cold, is a respiratory infection but is caused by an entirely different group of viruses - namely the influenza A, B and C viruses. Perhaps the best way to prevent the flu is to get an annual flu shot before the flu season hits.
I called Lufthansa, and they told me that there are Economy Plus seating sections on the Bangalore to Frankfurt and Frankfurt to Chicago legs. But, since I bought tickets through United, they told me I can't get any seat assignments until check-in in Bangalore unless I work with United.
The stats on Lufthansaâs Premium Economy seat are reasonably impressive. The company claims a 50% increase in passenger space, though a decent amount of that is at the shoulders, not the waist/seat cushion part of the seat. Depending on where you want/need the extra space the 50% number may be a bit less realistic.