Would the effectiveness of the flu vaccine be affected depending on the person's state of health at injection time? My mom is down with a severe cold (not flu) and she wants to wait until she recovers fully before getting the flu vaccine. Question is - would the vaccine be less effective if she got the injection now or it wouldn't matter at all? A negative might be that she might get more sick. But besides that, would the EFFICACY of the vaccine be compromised if she got it right now, as opposed to when she is in optimal health? Or is that not a factor? TIA.