Lessons learned concerning vaccine safety.

The safety of vaccines is an issue that has been with us ever since Jenner, and it will not go away. The author argues that despite what may seem a waste of energy, most proposed relationships between vaccines and reactions must be thoroughly investigated, as some have been proved correct. Investigations that show the putative relationship to be incorrect serve as examples of scientific rigor, which are valuable for the public. The author draws eight lessons for the future from our recent experiences.