The most influential measure to prevent infections in all of recorded history has been hand hygiene. When Dr. Semmelweis ordered all physicians and medical students to thoroughly wash their hands in chlorinated lime in 1847, the rate of infections plummeted.
As such, hand hygiene is not only about preventing infections, but also controlling antibiotic resistance. Hand hygiene is the single most important – and most cost-effective – measure to control spread of pathogens whether resistant to antibiotics or not.
How does hand hygiene work?
The most influential measure to prevent infections in all of recorded history has been hand hygiene. Before the time of Ignaz Semmelweis (1818-1865), physicians could move between wards without washing their hands. As an example, a physician could go directly from an autopsy to a delivery. Childbed fever killed 5-10% of all women in obstetric wards run by physicians, which was 10-20 times more than in wards run by midwives. When Dr. Semmelweis ordered all physicians and medical students to thoroughly wash their hands in chlorinated lime (i.e. bleach) in 1847, the rate of infections plummeted. Interestingly, this highly effective intervention was done before it was understood that bacteria cause disease.
In general, hand sanitation routines rely on two components: washing with soap and running water, and disinfection with alcohol hand sanitizer. The components act differently and are thus not wholly interchangeable.
Soap and water
Soap acts by making oily substances soluble in water. Infectious agents, bacteria and virus, stick to the oily substances and dirt on our hands. When soap, water and rubbing is added, the oils and dirt are lifted off from the skin and are rinsed away with the water. In the same process, most of the bacteria and viruses are flushed away. Notable here is that while soap does kill bacteria to some extent, it is not the main effector in hand washing. Notable downsides with soap and water are that water sinks are not possible to set up everywhere where hand sanitation is needed, and that washing with soap also removes the protective oils from the skin, causing dryness and skin lesions.
Alcohol hand sanitizers, on the other hand, act mainly by killing microorganisms. The alcohol acts on two levels:
- The alcohol destroys the outer cell membranes of the organisms by chemical interaction. Rubbing the hands enhances the interaction by the friction and by getting the alcohol into all small creases and folds of the skin.
- Alcohol denatures proteins, DNA and RNA vital for the microorganisms. Denaturing can be likened to unwinding a ball of yarn into a tangled mess – while the yarn is still whole, the tangled mess makes it unusable.
While alcohol hand sanitizers can be placed virtually anywhere or be carried around and do not dry out the hands as soap and water, they too have drawbacks. They do a poor job on dirty or greasy hands, and have limited effect on some microorganisms. As hand sanitizers do not flush away dirt or contaminants, they also do not remove residues of e.g. body fluids.
Common guidelines for hand hygiene
The above-mentioned differences are the reason why hand hygiene guidelines generally recommend using both soap and water and sanitizer.
Hands are to be washed when:
- Coming to and leaving the healthcare facility.
- After contact with e.g. body fluids or diarrhoea.
- When the hands are visibly dirty.
- After toilet visits.
Alcohol sanitizers are to be used in between, in accordance with the five moments for hand hygiene:
- Before patient contact.
- Before aseptic tasks
- After body fluid exposure risk
- After patient contact
- After contact with patient surroundings
Hand hygiene interventions
Many hand hygiene interventions focus on healthcare facilities, where the necessary measures are relatively easy to implement. For these settings, the WHO and others have developed several resources and tools. The necessary measures include technical improvements such as hand washing stations near all points of care, access to hand sanitizers and good sanitary solutions, such as piped water supply, clean toilets/latrines and proper handling of latrine waste. In terms of education, staff needs to be trained to understand the importance of hand hygiene and to make use of the technical solutions and guidelines for hand hygiene. It is also necessary to understand that healthcare staff set an example of good hygiene routines for the patients they meet.
In the community, the sanitary solutions needed are similar to the ones in health-care. There are several studies on how hand-washing rates can be improved in the community. Educational measures include understanding the importance of hand hygiene in daily life: to wash hands before handling food, after toilet visits and when caring for sick family members. However, alcohol sanitizers are mostly not needed. In these settings, it is also important to remember that not all bacteria are harmful. Many of the bacteria in our microbiome are shared within the family. These bacteria are not only good for us, but are necessary for our health. Thus some of the rigorous hygiene measures used in healthcare may not be necessary in the community. But it is equally important to remember that pathogens are spread within the family, especially via food.
There are several initiatives to teach better hand hygiene using more unconventional teaching means – both for the public and for hospital staff. Perhaps students listen better when washing hands “Gagnam style”, or health care personnel remember to disinfect catheter hubs when they hear the catchy ”Scrub the hub” song? While there are no studies on such efforts, experiences from marketing show that music and humour are effective means to spread a message and make it stick.
Neither of these two hand hygiene measures acts via mechanisms that are related to antibiotics or antibiotic resistance. As such, hand hygiene is not only about preventing infections, but also controlling antibiotic resistance. Hospital acquired infections are costly in both economy and human suffering. The bacteria causing them are also frequently highly resistant to antibiotics, especially in intensive care units where antibiotic use is abundant, and the bacteria may spread throughout a hospital and into the community. Hand hygiene is the single most important – and most cost-effective – measure to control spread of pathogens whether resistant to antibiotics or not.
In an old study from 1980, the effect of hand hygiene measures was investigated. Healthcare workers’ clean hands were contaminated with staphylococci or Gram-negative bacteria, followed by washing with soap and water and/or disinfectants. The study showed that almost all the bacteria were removed by disinfection with 70% ethanol (standard hand sanitizer), while up to 23% of the bacteria remained after washing with liquid soap for 15 seconds.