World Hand Hygiene Day

Today, 5 May, is World Hand Hygiene Day – an initiative promoted by the World Health Organisation to remind us that hand hygiene remains one of the most effective tools in preventing infection and ensuring public health. This year’s campaign – “Gloves, sometimes. Hand hygiene, always” – is a reminder to everyone, from citizens to healthcare professionals: hand hygiene remains one of the most powerful tools we have to prevent infections. A simple act, with a pivotal role in the history of medicine.

Hand hygiene, Semmelweis’ observations, and puerperal fever

Vienna, mid-19th century. Across European hospitals, many women died shortly after childbirth due to puerperal fever, a severe and often fatal infection whose cause remained unknown. At the time, antibiotics didn’t exist, and knowledge about how infections spread was still in its infancy. Only later would the germ theory, thanks to Louis Pasteur, transform the scientific landscape.

Ignaz Philipp Semmelweis, a young Hungarian physician working at the Vienna General Hospital, was struck by the difference in mortality rates between two maternity wards: in one, 10–15% of patients died; in the other, just over 1-2%. Both clinics admitted similar patients under similar conditions. Yet only one – the one staffed by doctors – showed such alarming mortality. The other, mainly managed by midwives, had much better outcomes.

Semmelweis developed a hypothesis: doctors were transmitting an unknown harmful agent on their unwashed hands – particularly after performing autopsies and before assisting in deliveries. He introduced a new rule: all doctors and medical students were required to wash their hands with a calcium chloride solution before entering the ward. The results were immediate: mortality dropped dramatically to 1–2%. A verifiable breakthrough, grounded in observation and systematic data comparison.

Semmelweis’ story is recounted in Childbed Fever: A Scientific Biography of Ignaz Semmelweis and in the more recent Il morbo dei dottori. La strana storia di Ignác Semmelweis (Codice Edizioni, 2020), which reconstruct the events from both a scientific and personal angle. His findings were not immediately accepted by the scientific community. Less than a decade later, he died in an asylum at just 47, shunned by colleagues and, according to some historians, possibly suffering from early-onset Alzheimer’s disease.

Historical factors also contributed to his institutionalization, such as the internal tensions within the Austro-Hungarian Empire and the Hungarian uprising of 1848, which discredited Hungary’s ruling elite and added to his marginalization. A tragic fate, yet one that does not diminish the legacy: more than a century later, Semmelweis’ insights are now recognized as a cornerstone of modern clinical practice.

From scientific discovery to daily routine

“Today, what was once Semmelweis’ intuition is scientific certainty: hand hygiene is the first, simplest, and most effective preventive measure we have,” says Elena Azzolini – Associate Professor of Public Health at Humanitas University and Deputy Medical Director at Humanitas.

“Over time, the practice has evolved: from early empirical recommendations to the WHO’s ‘5 moments’ for hand hygiene in healthcare, from soap and water to alcohol-based solutions – now fast-acting and widely available. Today, we have better tools and deeper knowledge, but the principle remains unchanged: protecting others starts with a simple act, done well, done consistently. No technology can replace it,” Azzolini concludes. “It’s a gesture that unites us as healthcare professionals and as responsible citizens.”

Learning by doing: a day of hygiene awareness at Humanitas Ospital

To mark World Day, the nursing students of Humanitas University have organised a special awareness activity at the entrance of IRCCS Istituto Clinico Humanitas, with an information point designed for healthcare professionals and open to all hospital visitors. As part of the activity, participants can use fluorescein gel and an ultraviolet lamp to immediately check how effective their handwashing is and see which areas they may have missed — a practical way to turn a routine habit into a conscious and meaningful action.