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alex3619 is making a lot of sense.
There is not a single correct answer for all of us. You have to consider all the issues and make the best decision you can for yourself.
My daughter and I both got H1N1 in the 2009 outbreak when our GP wouldn't give us the vaccine because he didn't believe we were in an at-risk population. We were both sick for months, and both got pneumonia. We both had a huge decline in health and I never got all the way back to where I was pre-H1N1.
We get flu shots every year at the recommendation of our ME/CFS specialists. We don't get live virus vaccines. This year our specialist advised/reminded us to get the preservative-free one, which gave neither of us any trouble. In the past I've had a week or so of a little extra fatigue and muscle aches with flu shots, but not with the preservative-free this year. I'd still rather have the week of minor symptoms than the weeks (and even months) of misery I've had with the flu in the past.
However, my daughter is in college and I tutor, both situations which expose us to more infections than some ME/CFS patients encounter. People who are housebound and without a lot of outside exposure have a much lower risk of infection, so the vaccine might not be worth it to them.
Also, some of us don't seroconvert, so the vaccine could be pointless. And some people react badly to vaccines in any case, so if you've had a bad reaction in the past, getting another is probably not a good idea. These decisions are never easy for us. **sigh**