There are over 10,000 to 10 million bacteria on our hands right now (Pidot et al., 2018). While most of these germs do not pose a health threat, the aim is to reduce the disease-causing bacteria to levels low enough for your immune system to handle (Mehtar et al., 2018). According to reports by the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO), poor hand hygiene is the number one contributing factor for the spread of infections. While washing your hands with warm water and soap remains the gold standard for hand hygiene (Mathur 2011), hand sanitisers are an excellent alternative to prevent infections caused by disease-causing microbes when soap and water aren’t available (FDA 2019). “Improved adherence to hand hygiene (i.e. hand washing or use of alcohol-based hand rubs) has been shown to terminate outbreaks in health care facilities, to reduce transmission of antimicrobial-resistant organisms (e.g. methicillin-resistant Staphylococcus aureus) and reduce overall infection rates (CDC, 2020).
There are two main types of hand sanitisers: alcohol-based hand sanitisers and alcohol-free hand sanitisers. This article will show you which of these two are more effective at keeping your hands germ-free and which is better for your skin.
How effective are Alcohol-based Hand Sanitiser?
A 2020 scientific review of alcohol-based hand sanitisers found that most contain isopropanol, ethanol, n-propanol, or a combination of them (Gold et al. 2020). Hand sanitisers work because of their antiseptic ingredients – they disrupt the cellular metabolism of the cell, effectively killing them (TGA, 2020) Alcohol is known to effectively kill a wide range of pathogens which include Pseudomonas Aeruginosa, Salmonella Typhosa, and Staphylococcus Aureus (Berardi et al. 2020). This is especially important in a hospital environment as patients and healthcare workers have high exposure to numerous bacteria and viruses every day.
Alcohol-based hand sanitisers effectiveness is dependant on the concentration levels and ingredient formulation. The CDC recommends that sanitizers should contain between 60% to 95% alcohol to effectively kill germs on the hands (CDC, 2018). Ethanol seems to be the most effective against viruses (Krampt, 2018), but propanols are better at killing bacteria, so a hand sanitiser with a combination of these two would seem ideal.
In addition to the efficacy level, ethanol and isopropanol kill pathogens very quickly, within a few seconds. This is important in fast-paced environments such as hospitals or clinics where healthcare workers cannot afford to wait for long periods of time for an antiseptic agent to disinfect their hands. Within a few seconds, alcohol can kill most non-spore-forming bacteria and decrease rates of infections (Krampf and Kramer, 2004). There are hand sanitisers that are highly effective with kill log rate of over 99.99999% and low contact time of under 1 minute.
How effective are alcohol-free hand sanitiser at killing bacteria?
In comparison, alcohol-free hand sanitisers often utilize the organic compound benzalkonium chloride as the active ingredient. Benzalkonium chloride has been recognised for a long time as an effective antibacterial and antiseptic agents but is less effective than alcohol (Nameth, 2010) Hand sanitisers without 60-95% alcohol may not work equally well for many types of germs; and merely reduce the growth of germs rather than kill them outright (CDC, 2020).
It should be known that although Benzalkonium chloride is widely used, there is no standardised antiseptic agent (CDC, 2020) and therefore makes it very difficult to assess the effectiveness of alcohol-free hand sanitisers. The CDC also do not give guidelines on the volume of antiseptic agents that should be used (unlike the case in alcohol-based hand sanitisers) because the efficacy rate may not necessarily be proportionate to the volume (CDC, 2020).
To date, the WHO does not recommend the use of alcohol-free hand sanitisers in clinical settings (WHO, 2009).
Do alcohol-based hand sanitisers damage your hands?
Alcohol-based hand sanitisers have been associated with a variety of skin reactions such as irritant contact dermatitis, which can present as dryness, itching, irritation, and skin cracking (Gold et al. 2020). Alcohol may strip the natural oils that retain moisture on the hands, however, this is short-lived as the skin will reproduce the oils as alcohol quickly dries off from the skin (Krampf and Kramer, 2004).
In addition, most alcohol-based hand sanitisers contain ingredients that help the skin retain moisture to minimise any damage that happens. For instance, humectants including propylene glycol are added to hand sanitisers, like PrimeOn Hand Sanitiser, to attract moisture to the skin surface (Berardi et al., 2020. and retain water within the skin layers. Overall, the application of ABHRs remains more versatile, convenient, quick and less irritating than handwashing with soap and water (Berardi et al. 2020).
Hand sanitiser should not replace normal handwashing and do not remove dirt and grime effectively. When hands are visibly soiled, they need to be cleaned with soap and water (CDC, 2020). A hand sanitiser can then be applied to kill any remaining germs.
Berardi, A., Perinelli, D., Merchant, H., Bisharat, L., Basheti, I., Bonacucina, G., Cespi, M. and Palmieri, G., 2020. Hand sanitisers amid CoViD-19: A critical review of alcohol-based products on the market and formulation approaches to respond to increasing demand. International Journal of Pharmaceutics, 584, p.119431.
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