Perception of risk of vaccine adverse events: a historical perspective.

The psychology of risk perception puts the emotive evaluation of the risks associated with vaccination incorrectly into a high risk category. This causes a wariness of taking vaccines that has its roots in the deep history of people. Humans do not seek to disturb the status quo by which they live. So the introduction of a vaccinal material into a healthy baby requires courage and an educated anticipation that some important benefit will accrue to this act at some future date. This situation encourages the emergence of a resistance to vaccines and the establishment of propagandists and movements to promote such ideas. The origin and development of such movements and the arguments which they prefer are the subject of this paper. These are based on religion in the first instance and then they widen to include the practical and technical problems which the early vaccinators experienced. The making of vaccination against smallpox compulsory at law in the UK in (effectively) 1867, inspired a most active and able opposition to vaccination. The concerns which such movements raise and ways in which they may be addressed are dealt with in the final sections.