Let's say only 1 lung is damaged. if the damaged area gets the flu pneumonia, does it affect the other healthy lung's chance of getting it, too?

"flu" ?: True influenza is a systemic infection, and the pulmonary component will affect both lungs simultaneously, so if influenza or viral pneumonia is detected, adequate supportive treatment will also treat both lungs.

Agree with Dr. B: Flu affects both lungs, however, the damaged lung may be more susceptible to superimposed bacterial infection. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/.