I had the shingles vaccine last April. I didn't notice any effect on BG numbers. I did get some swelling/redness at the injection site, but nothing too serious. Even if I'd had BG problems, I would still get the vaccine in hopes that it will protect me from shingles or at least protect me from a severe case.
I'm very pro-vaccine and am not quick to blame BG problems on vaccines. I know that I don't want to get the flu and I don't want to get shingles. So give me the vaccine and I'll hope that it works.