Soap vs Hand Sanitiser, Let's Rumble

Karina Dembla 

20 seconds. Running water. Soap. Palm to palm, back of the hand, in between the fingers and under the fingernails. Sound familiar? These are the steps to simple routine handwashing. It drastically reduces hand microbial contamination and limits the transfer of microbes on to surfaces, other body parts and people. Soap is composed of a mixture of fats, water and alkali. Its molecular structure consists of a hydrophilic (water-loving) head and a hydrophobic (water-hating) tail. The hydrophobic tail embeds itself into the lipid membrane of pathogens, disrupting their weak chemical bonds. The soap molecule then assembles into micelles around these pathogen fragments, making them soluble in water. The friction created during lathering and rinsing with water, allows the residues to be washed off the surface of hands. 

In today’s world, where convenience and accessibility are the norms, many individuals rely on the use of alcohol-based hand sanitisers (ABHS). The product should be applied and rubbed on the surface of both hands until they are dry. The Food and Drug Administration suggests that ABHS should contain at least 60-75% alcohol, either ethanol or isopropanol, as they mediate germicidal mechanisms. Alcohol denatures vital proteins and interferes with cell metabolism whilst water, another fundamental ingredient, delays the evaporation of alcohol to prolong the effects of sanitisers. Chemical companies accelerated ABHS production during the H1N1 flu outbreak in 2009 and are continuing this trend in response to the novel coronavirus. 

A primary concern for hospitals and health-care workers is reducing and eliminating the transfer of germs between patients. The introduction of the convenient ABHS has improved infection control and has proven to be superior to no handwashing at all. However, many studies have raised concerns about the efficacy of ABHS. ABHS has shown to be effective against a selection of pathogens such as rhinovirus, adenovirus, rotavirus and influenza A although not against norovirus, clostridium difficile and influenza B. A large number of bacterial strains are starting to evolve and become increasingly tolerant to alcohol. Therefore, sanitisers have a limited role in battling microorganism hand colonization. Moreover, ABHS does not function on visibly greasy hands, a factor that could leave large numbers of people unprotected. Additionally, an element that has been at the forefront of safety concerns is that of possible unintentional ingestion by children as well as the highly flammable properties of alcohol. 

Can ABHS replace hand soap? To put it simply, no. However, it can provide a suitable alternative when water and soap are not available. The action of hand soap is not restricted to certain microbes and can remove chemical residues, but 20% of the population do not perform handwashing despite the undeniable benefits. Ever since Dr. Semmelweis, a pioneer in the discovery of antiseptic practice, discovered the ability of routine hand washing to prevent the spread of disease, it has solidified itself as the most reliable method. So, what are you waiting for? 

References:
https://www.ncbi.nlm.nih.gov/pubmed/16023513
https://iafp.confex.com/iafp/2012/webprogram/Paper2281.html
http://www.handhygiene.net/alcohol-free-vs-alcohol-based-hand-sanitizers/
http://whqlibdoc.who.int/publications/2009/9789241597906_eng.pdf.
https://chem.ku.edu/sites/chem.ku.edu/files/docs/CHEM190/soap.pdf
https://www.ncbi.nlm.nih.gov/pubmed/21318017
https://www.science.org.au/curious/people-medicine/hand-sanitiser-or-soap-making-informed-choice-covid-19
https://www.ncbi.nlm.nih.gov/books/NBK144041/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2825992/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805232/ 
https://www.cdc.gov/handwashing/when-how-handwashing.html
https://www.ncbi.nlm.nih.gov/pubmed/21691245
https://www.ncbi.nlm.nih.gov/pubmed/19715426
http://www.dpic.org/article/professional/alcohol-based-hand-sanitizer-safety
https://stm.sciencemag.org/content/10/452/eaar6115
https://www.utoronto.ca/news/do-hand-sanitizers-really-work

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