Hygiene — Twenty seconds that changed medicine

In 1847, Ignaz Semmelweis proved that doctors washing their hands dropped death rates in maternity wards from 18% to 2%. He was ridiculed. He died in an asylum. It took decades for handwashing to become standard practice. He was right. The world was not ready.

• Wash your hands with soap for 20 seconds. Soap breaks the outer layer of viruses and bacteria. Water alone does not.
• The WHO estimates that handwashing with soap could prevent about 1 million deaths per year worldwide.