Hand washing (or handwashing), also known as hand hygiene, is the act of cleaning one's hands with soap (or equivalent materials) and water to remove viruses/bacteria/microorganisms, dirt, grease, or other harmful and unwanted substances stuck to the hands. Drying of the washed hands is part of the process as wet and moist hands are more easily recontaminated.The World Health Organization recommends washing hands for at least 20 seconds before/after the following:
Before and after caring for any sick person
Before, during, and after preparing food
After using the toilet (for urination, defecation, menstrual hygiene),
After helping someone who just used the toilet
After blowing one's nose, or coughing or sneezing
After touching an animal, animal feed or animal waste
After touching garbage
After coming from hospital
After any travel
However, if soap and water are not available, hand sanitizer that is at least 60% (v/v) alcohol in water (specifically, ethanol or isopropyl alcohol/isopropanol (rubbing alcohol)) can be used instead, unless hands are visibly excessively dirty or greasy. When both hand washing and using hand sanitizer are not available, hands can be cleaned with uncontaminated ash and clean water, although the benefits and harms are uncertain for reducing the spread of viral or bacterial infections. However, frequent hand washing can lead to skin damage due to drying of the skin.Hand washing with soap – often, and throughout the day – prevents the spread of many diseases, for example diarrhoea and cholera which are transmitted through fecal–oral route. People can also become more easily infected with respiratory diseases such as the common cold, influenza, SARS, MERS and COVID-19 if they do not wash their hands before touching their eyes, nose or mouth.
Medical hand hygiene refers to hygiene practices related to medical procedures. Hand washing before administering medicine or medical care can prevent or minimize the spread of disease. The main medical purpose of washing hands is to cleanse the hands of pathogens (bacteria, viruses, or other microorganisms) and chemicals which can cause harm. This is especially important for people who handle food or work in the medical field, but also an important practice for the general public.
The World Health Organisation defines critical moments for health-care worker hand hygiene, using the 'My 5 Moments for Hand Hygiene approach'.
Before touching a patient,
Before aseptic procedures,
After body fluid exposure/risk,
After touching a patient, and
After touching patient surroundings
Symbolic hand washing, using water but no soap to wash hands, is a part of ritual hand washing featured in many religions, including the Baháʼí Faith, Hinduism, tevilah and netilat yadayim in Judaism, Lavabo in Christianity, and Wudhu in Islam. Religions also prescribe hygienic hand washing, especially after certain actions. Hinduism, Judaism and Islam mandate washing of hands after using the toilet. And, Hinduism, Buddhism, Sikhism, Judaism and Islam mandate washing of hands before and after every meal.