So, we should all get a useless and possibly dangerous vaccination because your fiancée is a heavy smoker with weak lungs?
Get real, flu shots are useless. The flu virus mutates every year hence the shots are not effective for the new strain. You've got an immune system don't you, let it fight. And if somebody is stupid enough to smoke to the extent that his/her lungs are weak I have no sympathy.
You should research it, talk to pharmacists before advising "everybody".