Prior to last year, I hadn't had a flu shot in decades and only had the flu once, about 10 years ago. It was a 24-hour version. Very unpleasant, as I recall.
Last year, while visiting the hospital for a follow-up visit with my radiologist, they were offering free flu shots if you were over 60 I qualified, so I got one. No ill effects ensued. I figured that with my body then working hard to heal from surgery and radiation, it couldn't hurt. I guess it worked. I didn't get the flu. My doctor never mentioned getting a flu shot and I never thought to ask but I haven't had one this year. If the opportunity arises, I'll get one but odds are, at this late date, I'll pass. I don't believe there is any correlation between having an acoustic neuroma and having a flu shot other than the recent post-surgical/radiation patient's recovery process causing the body's immune system to be at less than optimal levels, possibly allowing one to be more vulnerable to the influenza virus du jour. However, that's just the opinion of a non-physician and not one that is, necessarily, medically accurate.
Jim