Hand washing with soap and water at a kitchen sink
|Other names||Handwashing, hand hygiene|
Hand washing (or handwashing), also known as hand hygiene, is the act of cleaning one's hands for the purpose of removing soil, grease, microorganisms, or other unwanted substances.
Hand washing with soap consistently at certain "critical moments" during the day prevents the spread of many diseases, for example diarrhoea and cholera, which are transmitted through fecal–oral route. People can also become infected with respiratory diseases such as influenza or the common cold, for example, if they do not wash their hands before touching their eyes, nose, or mouth (i.e., mucous membranes). The five critical moments during the day where washing hands with soap is important include: before and after defecation, after cleaning a child's bottom or changing nappies, before feeding a child, before eating and before and after preparing food or handling raw meat, fish, or poultry. If water and soap are not available, hands can be cleaned with ash.
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 that can cause disease.) and chemicals which can cause harm or diseases. This is especially important for people who handle food or work in the medical field, but also an important practice for the general public.
Hand washing has many health benefits, including minimizing the spread of influenza, coronavirus, and other infectious diseases; preventing infectious causes of diarrhea; decreasing respiratory infections; and reducing infant mortality rate at home birth deliveries. A 2013 study showed that improved hand washing practices may lead to small improvements in the length growth in children under five years of age. In developing countries, childhood mortality rates related to respiratory and diarrheal diseases can be reduced by introducing simple behavioral changes, such as hand washing with soap. This simple action can reduce the rate of mortality from these diseases by almost 50%. Interventions that promote hand washing can reduce diarrhoea episodes by about a third, and this is comparable to providing clean water in low income areas. 48% of reductions in diarrhoea episodes can be associated with hand washing with soap.
Hand washing with soap is the single most effective and inexpensive way to prevent diarrhea and acute respiratory infections (ARI), as automatic behavior performed in homes, schools, and communities worldwide. Pneumonia, a major ARI, is the number one cause of mortality among children under five years old, taking the lives of an estimated 1.8 million children per year. Diarrhea and pneumonia together account for almost 3.5 million child deaths annually. According to UNICEF, turning hand washing with soap before eating and after using the toilet into an ingrained habit can save more lives than any single vaccine or medical intervention, cutting deaths from diarrhea by almost half and deaths from acute respiratory infections by one-quarter. Hand washing is usually integrated together with other sanitation interventions as part of water, sanitation and hygiene (WASH) programmes. Hand washing also protects against impetigo which is transmitted through direct physical contact.
A small detrimental effect of hand washing is that frequent hand washing can lead to skin damage due to drying of the skin. A 2012 Danish study found that excessive hand washing can lead to an itchy, flaky skin condition known as hand eczema or hand dermatitis, which is especially common among health-care workers. Too frequent hand washing is also seen as one of the symptoms of obsessive-compulsive disorder (OCD).
There are five critical times during the day where washing hands with soap is important to reduce fecal-oral transmission of disease: after using the bathroom (urination, defecation), after cleaning a child's bottom (changing nappies), before feeding a child, before eating and before/after preparing food or handling raw meat, fish, or poultry. Other occasions when correct handwashing technique should be practiced in order to prevent the transmission of disease include before and after treating a cut or wound; after sneezing, coughing, or blowing your nose; after touching animal waste or handling animals; and after touching garbage.
In many countries, there is a low rate of hand washing with soap. A study of hand washing in 54 countries in 2015 found that on average, 38.7% of households practiced hand washing with soap.
A 2014 study showed that Saudi Arabia had the highest rate of 97 percent; the United States near the middle with 77 percent; and China with the lowest rate of 23 percent.
Several behaviour change methodologies now exist to increase uptake of the behaviour of hand washing with soap at the critical times.
Group hand washing for school children at set times of the day is one option in developing countries to engrain hand washing in children's behaviors. The "Essential Health Care Program" implemented by the Department of Education in the Philippines is an example of at scale action to promote children's health and education. Deworming twice a year, supplemented with washing hands daily with soap, brushing teeth daily with fluoride, is at the core of this national program. It has also been successfully implemented in Indonesia.
Removal of microorganisms from skin is enhanced by the addition of soaps or detergents to water. The main action of soaps and detergents is to reduce barriers to solution, and increase solubility. Water alone is an inefficient skin cleanser because fats and proteins, which are components of organic soil, are not readily dissolved in water. Cleansing is, however, aided by a reasonable flow of water..
Solid soap, because of its reusable nature, may hold bacteria acquired from previous uses. A small number of studies which have looked at the bacterial transfer from contaminated solid soap have concluded transfer is unlikely as the bacteria are rinsed off with the foam. The CDC still states "liquid soap with hands-free controls for dispensing is preferable".
Antibacterial soaps have been heavily promoted to a health-conscious public. To date, there is no evidence that using recommended antiseptics or disinfectants selects for antibiotic-resistant organisms in nature. However, antibacterial soaps contain common antibacterial agents such as triclosan, which has an extensive list of resistant strains of organisms. So, even if antibiotic resistant strains aren't selected for by antibacterial soaps, they might not be as effective as they are marketed to be. Besides the surfactant and skin-protecting agent, the sophisticated formulations may contain acids (acetic acid, ascorbic acid, lactic acid)as pH regulator, antimicrobially active benzoic acid and further skin conditioners (aloe vera, vitamins, menthol, plant extracts).
A comprehensive analysis from the University of Oregon School of Public Health indicated that plain soaps are as effective as consumer-grade anti-bacterial soaps containing triclosan in preventing illness and removing bacteria from the hands.
Hot water that is comfortable for washing hands is not hot enough to kill bacteria. Bacteria grow much faster at body temperature (37 C). However, warm, soapy water is more effective than cold, soapy water at removing natural oils which hold soils and bacteria. Contrary to popular belief however, scientific studies have shown that using warm water has no effect on reducing the microbial load on hands.
A hand sanitizer or hand antiseptic is a non-water-based hand hygiene agent. In the late 1990s and early part of the 21st century, alcohol rub non-water-based hand hygiene agents (also known as alcohol-based hand rubs, antiseptic hand rubs, or hand sanitizers) began to gain popularity. Most are based on isopropyl alcohol or ethanol formulated together with a thickening agent such as Carbomer (polymer of acrylic acid) into a gel, or a humectant such as glycerin into a liquid, or foam for ease of use and to decrease the drying effect of the alcohol. Adding diluted hydrogen-peroxide increases further the antimicrobial activity.
Hand sanitizers containing a minimum of 60 to 95% alcohol are efficient germ killers. Alcohol rub sanitizers kill bacteria, multi-drug resistant bacteria (MRSA and VRE), tuberculosis, and some viruses (including HIV, herpes, RSV, rhinovirus, vaccinia, influenza, and hepatitis) and fungi. Alcohol rub sanitizers containing 70% alcohol kill 99.97% (3.5 log reduction, similar to 35 decibel reduction) of the bacteria on hands 30 seconds after application and 99.99% to 99.999% (4 to 5 log reduction) of the bacteria on hands 1 minute after application.
Hand sanitizers are most effective against bacteria and less effective against some viruses. Alcohol-based hand sanitizers are almost entirely ineffective against norovirus or Norwalk type viruses, the most common cause of contagious gastroenteritis.
Enough hand antiseptic or alcohol rub must be used to thoroughly wet or cover both hands. The front and back of both hands and between and the ends of all fingers are rubbed for approximately 30 seconds until the liquid, foam or gel is dry. Finger tips must be washed well too, rubbing them in both palms.
The US Center for Disease Control and Prevention recommends hand washing over hand sanitizer rubs, particularly when hands are visibly dirty. The increasing use of these agents is based on their ease of use and rapid killing activity against micro-organisms; however, they should not serve as a replacement for proper hand washing unless soap and water are unavailable.
Frequent use of alcohol-based hand sanitizers can cause dry skin unless emollients and/or skin moisturizers are added to the formula. The drying effect of alcohol can be reduced or eliminated by adding glycerin and/or other emollients to the formula. In clinical trials, alcohol-based hand sanitizers containing emollients caused substantially less skin irritation and dryness than soaps or antimicrobial detergents. Allergic contact dermatitis, contact urticaria syndrome or hypersensitivity to alcohol or additives present in alcohol hand rubs rarely occur. The lower tendency to induce irritant contact dermatitis became an attraction as compared to soap and water hand washing.
Despite their effectiveness, non-water agents do not cleanse the hands of organic material, but simply disinfect them. It is for this reason that hand sanitizers are not as effective as soap and water at preventing the spread of many pathogens, since the pathogens still remain on the hands.
Alcohol-free hand sanitizer efficacy is heavily dependent on the ingredients and formulation, and historically has significantly under-performed alcohol and alcohol rubs. More recently, formulations that use benzalkonium chloride have been shown to have persistent and cumulative antimicrobial activity after application, unlike alcohol, which has been shown to decrease in efficacy after repeated use, probably due to progressive adverse skin reactions.
Many people in low-income communities cannot afford soap and use ash or soil instead. Ash or soil may be more effective than water alone, but may be less effective than soap. Evidence quality is poor. One concern is that if the soil or ash is contaminated with microorganisms it may increase the spread of disease rather than decrease it. Like soap, ash is also a disinfecting agent because in contact with water, it forms an alkaline solution. WHO recommended ash or sand as alternative to soap when soap is not available.
The most commonly missed areas are the thumb, the wrist, the areas between the fingers, and under fingernails. Artificial nails and chipped nail polish may harbor microorganisms. Moisturizing lotion is often recommended to keep the hands from drying out; dry skin can lead to skin damage which can increase the risk for the transmission of infection.
Various low-cost options can be made to facilitate hand washing where tap-water and/or soap is not available e.g. pouring water from a hanging jerrycan or gourd with suitable holes and/or using ash if needed in developing countries.
In situations with limited water supply (such as schools or rural areas in developing countries), there are water-conserving solutions, such as "tippy-taps" and other low-cost options. A tippy-tap is a simple technology using a jug suspended by a rope, and a foot-operated lever to pour a small amount of water over the hands and a bar of soap.
Effective drying of the hands is an essential part of the hand hygiene process, but there is some debate over the most effective form of drying in public washrooms. A growing volume of research suggests paper towels are much more hygienic than the electric hand dryers found in many washrooms.
In 2008, a study was conducted by the University of Westminster, London, and sponsored by the paper-towel industry the European Tissue Symposium, to compare the levels of hygiene offered by paper towels, warm-air hand dryers and the more modern jet-air hand dryers. The key findings were:
The scientists also carried out tests to establish whether there was the potential for cross contamination of other washroom users and the washroom environment as a result of each type of drying method. They found that:
In 2005, in a study conducted by TÜV Produkt und Umwelt, different hand drying methods were evaluated. The following changes in the bacterial count after drying the hands were observed:
|Drying method||Effect on bacterial count|
|Paper towels and roll||Decrease of 24%|
|Hot-air dryer||Increase of 12%|
Many different hand dryer manufacturers exist, and hand driers have been compared against drying with paper towels.
Medical hand-washing became mandatory long after Hungarian physician Ignaz Semmelweis discovered its effectiveness (in 1846) in preventing disease in a hospital environment. There are electronic devices that provide feedback to remind hospital staff to wash their hands when they forget. One study has found decreased infection rates with their use.
Medical hand-washing is for a minimum of 15 seconds, using generous amounts of soap and water or gel to lather and rub each part of the hands. Hands should be rubbed together with digits interlocking. If there is debris under fingernails, a bristle brush may be used to remove it. Since germs may remain in the water on the hands, it is important to rinse well and wipe dry with a clean towel. After drying, the paper towel should be used to turn off the water (and open any exit door if necessary). This avoids re-contaminating the hands from those surfaces.
The purpose of hand-washing in the health-care setting is to remove pathogenic microorganisms ("germs") and avoid transmitting them. The New England Journal of Medicine reports that a lack of hand-washing remains at unacceptable levels in most medical environments, with large numbers of doctors and nurses routinely forgetting to wash their hands before touching patients, thus transmitting microorganisms. One study showed that proper hand-washing and other simple procedures can decrease the rate of catheter-related bloodstream infections by 66 percent.
The World Health Organization has published a sheet demonstrating standard hand-washing and hand-rubbing in health-care sectors. The draft guidance of hand hygiene by the organization can also be found at its website for public comment. A relevant review was conducted by Whitby et al. Commercial devices can measure and validate hand hygiene, if demonstration of regulatory compliance is required.
The World Health Organization has "Five Moments" for washing hands:
The addition of antiseptic chemicals to soap ("medicated" or "antimicrobial" soaps) confers killing action to a hand-washing agent. Such killing action may be desired prior to performing surgery or in settings in which antibiotic-resistant organisms are highly prevalent.
To 'scrub' one's hands for a surgical operation, it is necessary to have a tap that can be turned on and off without touching it with the hands, some chlorhexidine or iodine wash, sterile towels for drying the hands after washing, and a sterile brush for scrubbing and another sterile instrument for cleaning under the fingernails. All jewelry should be removed. This procedure requires washing the hands and forearms up to the elbow, usually 2–6 minutes. Long scrub-times (10 minutes) are not necessary. When rinsing, water on the forearms must be prevented from running back to the hands. After hand-washing is completed, the hands are dried with a sterile cloth and a surgical gown is donned.
To reduce the spread of germs, it is better to wash the hands or use a hand antiseptic before and after tending to a sick person.
For control of staphylococcal infections in hospitals, it has been found that the greatest benefit from hand-cleansing came from the first 20% of washing, and that very little additional benefit was gained when hand cleansing frequency was increased beyond 35%. Washing with plain soap results in more than triple the rate of bacterial infectious disease transmitted to food as compared to washing with antibacterial soap.
Comparing hand-rubbing with alcohol-based solution with hand washing with antibacterial soap for a median time of 30 seconds each showed that the alcohol hand-rubbing reduced bacterial contamination 26% more than the antibacterial soap. But soap and water is more effective than alcohol-based hand rubs for reducing H1N1 influenza A virus and Clostridium difficile spores from hands.
Interventions to improve hand hygiene in healthcare settings can involve education for staff on hand washing, increasing the availability of alcohol-based hand rub, and written and verbal reminders to staff. There is a need for more research into which of these interventions are most effective in different healthcare settings.
In developing countries, hand washing with soap is recognized as a cost-effective, essential tool for achieving good health, and even good nutrition. However, a lack of reliable water supply, soap or hand washing facilities in people's homes, at schools and at the workplace make it a challenge to achieve universal hand washing behaviors. For example, in most of rural Africa hand washing taps close to every private or public toilet are scarce, even though cheap options exist to build hand washing stations. However, low hand washing rates rather can also be the result of engrained habits rather than due to a lack of soap or water.
The promotion and advocacy of hand washing with soap can influence policy decisions, raise awareness about the benefits of hand washing and lead to long-term behavior change of the population. For this to work effectively, monitoring and evaluation are necessary. A systematic review of 70 studies found that community-based approaches are effective at increasing hand washing in LMICs, while social marketing campaigns are less effective.
One example for hand washing promotion in schools is the "Three Star Approach" by UNICEF that encourages schools to take simple, inexpensive steps to ensure that students wash their hands with soap, among other hygienic requirements. When minimum standards are achieved, schools can move from one to ultimately three stars. Building hand washing stations can be a part of hand washing promotion campaigns that are carried out in order to reduce diseases and child mortality.
Few studies have considered the overall cost effectiveness of hand washing in developing countries in relationship to DALYs averted. However, one review suggests that promoting hand washing with soap is significantly more cost-effective than other water and sanitation interventions.
|Hand-pump or standpost||94|
|House water connection||223|
|Water sector regulation||47|
|Basic sanitation – construction and promotion||≤270|
|Sanitation promotion only||11.2|
The importance of hand washing for human health – particularly for people in vulnerable circumstances like mothers who had just given birth or wounded soldiers in hospitals – was first recognized in the mid 19th century by two pioneers of hand hygiene: the Hungarian physician Ignaz Semmelweis who worked in Vienna, Austria and Florence Nightingale, the English "founder of modern nursing". At that time most people still believed that infections were caused by foul odors called miasmas.
In the 1980s, foodborne outbreaks and healthcare-associated infections led the United States Centers for Disease Control and Prevention to more actively promote hand hygiene as an important way to prevent the spread of infection. The outbreak of swine flu in 2009 and the COVID-19 pandemic in 2020 led to increased awareness in many countries of the importance of washing hands with soap to protect oneself from such infectious diseases. For example, posters with "correct hand washing techniques" were hung up next to hand washing sinks in public toilets and in the toilets of office buildings and airports in Germany.
The phrase "washing one's hands of" something, means declaring one's unwillingness to take responsibility for the thing or share complicity in it. It originates from the bible passage in Matthew where Pontius Pilate washed his hands of the decision to crucify Jesus Christ, but has become a phrase with a much wider usage in some English communities.
In Shakespeare's Macbeth, Lady Macbeth begins to compulsively wash her hands in an attempt to cleanse an imagined stain, representing her guilty conscience regarding crimes she had committed and induced her husband to commit.
It has also been found that people, after having recalled or contemplated unethical acts, tend to wash hands more often than others, and tend to value hand washing equipment more. Furthermore, those who are allowed to wash their hands after such a contemplation are less likely to engage in other "cleansing" compensatory actions, such as volunteering.
Symbolic hand washing, using water but no soap to wash hands, is a part of ritual hand washing featured in many religions, including Bahá'í Faith, Hinduism, and tevilah and netilat yadayim in Judaism. Similar to these are the practices of Lavabo in Christianity, Wudu in Islam (see also Muslim hygienical jurisprudence) and Misogi in Shintō.
WHO/UNICEF Joint Monitoring Programme (JMP) for Water Supply and Sanitation[dead link]