This may be an impossible question to answer, but my father, in his eighties, refused a flu shot this year. He said he won't get one because it will make him sick. He has always been diligent in the past about getting one.
Over the age of 65 I've heard a double dose of the vaccine is reccomended. I've had mine but I'm frightened of him getting the flu and leading to pneumonia, and I take care of him. He does get out in public now and then mostly for grocery shopping.