The Semmelweis reflex or “Semmelweis effect” is a metaphor for the reflex-like tendency to reject new evidence or new knowledge because it contradicts established norms, beliefs or paradigms.

1848: Ignaz Phillip Semmelweis, Hung. physician, discovers the cause of puerperal fever; medical students are carrying the infection … to healthy women. He orders all medical students to wash their hands before examining patients; within months the mortality rate drops to near zero.  

1865: Semmelweis, his ideas rejected by the European medical community, dies of puerperal fever, the disease he fought to eradicate his entire life.*

Wash your hands. What a radical idea.

In 1861 Semmelweis published his principal work, Die Ätiologie, der Begriff und die Prophylaxis des Kindbettfiebers (The Etiology, Concept, and Prophylaxis of Childbed Fever). He sent it to all the prominent obstetricians and medical societies abroad, but the general reaction was adverse. The weight of authority stood against his teachings. He addressed several open letters to professors of medicine in other countries, but to little effect. At a conference of German physicians and natural scientists, most of the speakers—including the pathologist Rudolf Virchow—rejected his doctrine. The years of controversy gradually undermined his spirit. In 1865 he suffered a breakdown and was taken to a mental hospital, where he died. Ironically, his illness and death were caused by the infection of a wound on his right hand, apparently the result of an operation he had performed before being taken ill. He died of the same disease against which he had struggled all his professional life.