May 5: World Hand Hygiene Day

Manuel Van den Broucke, sports, society and politics correspondent, May 5, 2025

Methods for washing your hands

Three methods keep hands clean: washing with soap and water, alcohol-based hand rub, and surgical disinfection. Washing begins by wetting the hands entirely with warm water, then adding mild soap free of triclosan. Every area must be scrubbed: palms, backs of hands, spaces between fingers, thumbs and fingertips, for twenty seconds. Rinsing is done from the wrists toward the fingertips to carry away germs, then hands are dried by patting with a single-use towel, which is finally used to turn off the tap. Alcohol-based hand rub is used when hands are not visibly dirty. A dollop of gel containing 60-95% alcohol enriched with glycerin is applied, then rubbed over all surfaces until fully evaporated, about thirty seconds. For surgical disinfection, the forearms and hands are scrubbed for two minutes with a 4% chlorhexidine or 7.5% povidone-iodine solution, rinsed and dried with sterile towels before gloves are put on.

Mistakes to avoid

The first mistake is washing hands too quickly: stopping after twelve seconds reduces washing effectiveness by a third. Wearing rings, bracelets or a watch encourages germs to build up under the accessories. Long or false nails also promote the presence of Enterobacter cloacae; they are therefore banned in surgery. Using gel on visibly soiled hands does not work, because dirt blocks the action of the alcohol. Neglecting to dry hands increases the transfer of Pseudomonas aeruginosa a thousandfold, while highly alcoholic gels without moisturizing agents crack the skin and encourage the growth of yeasts such as Candida auris.

Pathogens transmitted by hands

Bacteria, viruses, fungi and even parasites easily settle on skin. Staphylococcus aureus, including the methicillin-resistant strain, survives for several hours on a moist hand and can cause abscesses or septicemia. Enterococcus faecium, resistant to vancomycin, is often transmitted via door handles in intensive care units. As for intestinal bacteria, a single handshake is enough to spread Klebsiella pneumoniae or Shigella dysenteriae, responsible for severe diarrhea. Clostridioides difficile spores cling to the folds of skin on the fingers and resist alcohol-based gel, which is why soap is necessary. Respiratory viruses such as rhinovirus remain infectious for forty-eight hours on unwashed hands, and SARS-CoV-2 for about eight hours.