Maybe we can make use of it later. Because smallpox no longer exists outside of a few high security laboratories, we no longer require immunization against smallpox, which was one of three major elements in the successful global eradication campaign. In the domain of controlled drugs, the successes of prevention are more difficult to find and have been more limited in scope. What is claimed as an ebbing due to change in public policy, law enforcement, or other public campaigns can in fact be something else. In the drug arena as in other sectors of public health work, our community leaders sometimes are able to ride to glory on the descending limb of an epidemic curve.
Tides change regularly without our help.
Another reason for difficulty in identifying truly successful drug prevention campaigns involves the character of drug-taking in our populations throughout history, which can change as rapidly as Proteus or grow a new head like Hydra. The story of drug epidemics is one of the diffusion of multiple innovations, spread from person to person, place to place, and over time. In recent history, efforts to dampen the spread of one innovation have been followed by change and adaptation toward novelty. What appears as a success of intervention may be displacement of an older innovation with its newer cousin. J. Anthony, Johns Hopkins University, March 2000.