There should be an 'early stages' warning for the 'omg this medicine increases risk of broken nails, and I wasn't warned, now I want one million dollars'.
Fact is all drugs have side effects, all drugs have risks. And by the sheer ammount of acetaminophen on the market and its risks I assume it's not science that's in play there, but rather politics and lobbying.
According to wikipedia, it took 4 years between Jenner's first inoculation attempt and when the British government passed the Vaccination Act (which banned variolation and provided free vaccination for all). Wikipedia also told me that after Salk developed his first vaccine in 1952 (which he confirmed initial human safety, basically what these trials actually set out to do by testing on himself and his family), they then conducted a field test with over 2 MILLION participants before finally declaring it effective in 1955.
It should be noted that detecting the effectiveness of either a smallpox or polio vaccine is much easier than Alzheimer's. For one thing, we aren't even sure exactly how Alzheimer's deals damage. You would -need- a relatively long term, and careful study to tease out real results.
