I too had a similar experience. My wife and I seemed to always catch something within a month after receiving the flu shot. After that, we stopped getting them. The first year I stopped, I did get a mild case of the flu (or something similar); however, since then I've rarely even had a cold. It's been about 6 years now and I know my immune system is much stronger than it was in the past when I'd always get the flu shot. I'll never take another vaccine again!