Knighted wrote, "With vaccines, the components are present in the body for a very brief period of time. So any side effects from it should show up fairly quickly. The lasting effect comes from the immune system's response and memory, not from the vaccine continually acting on the body for years. "

While I am enthusiastically pro-vaccine (and in fact got both versions of the shingles vaccine) I have to point out that some people do have a lasting effect from the immune system's response and memory. This first became publicized after the population-wide swine flu vaccination program in 1976. The program was officially halted on December 16, 1976, after the vaccine was linked to an increased risk of Guillain-Barré syndrome, a rare neurological disorder. I remember this well because I and my entire family got this vaccine. We were hit hard by the 1968 Hong Kong flu.

The risk of developing Guillain-Barré syndrome (GBS) after receiving a flu vaccine is extremely rare, occurring in about 1 to 2 people per million vaccinated. This translates to a percentage of roughly 0.0001% to 0.0002%. The risk is highly concentrated within the first 6 weeks following immunization. The majority of individuals return to normal health or independent walking within a year.

I don't let this minuscule risk prevent me from getting a flu shot every year. But the risk is non-zero.

Wendy