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.
Checked Baggage Summary. In general, Lufthansa allows one free bag of up to 23kg/50lbs for all Economy class passengers. Business class passengers are allowed 2 bags of 32kg/70lbs each, whereas First Class passengers are allowed 3 bags weighing up to 32kg each.