Schwarz copied a flier put out by the Centers for Disease Control and Prevention intended to combat various myths about the flu vaccine. It listed a number of common beliefs about the vaccine and indicated whether they were true or false. He then asked volunteers to read the flier. Some of them were old, some young, but shortly thereafter he found that many of the older people mistakenly remembered almost of a third of the false statements as being true, and after a few days young and old alike misclassified 40 percent of the myths as factual.
Even worse was that people now attributed these false beliefs to the CDC itself! In an effort to dispel misconceptions about the vaccine, the CDC had inadvertently lent its prestige to them. In many cases, truth and elucidation can actually strengthen misconceptions and make them more psychologically available.
You know, actually, that explains a lot.