sanitizer formulation with OPHARDT
Australian researches investigated what type of sanitizer are most popular.
Research

What sanitizer formulations do people prefer? And why?

Why do hand hygiene compliance levels remain so stubbornly low?

We have examined the lack of hygiene infrastructure, the need for improved group-based compliance monitoring and feedback, and the possibility of simplifying the steps to disinfect. A new study out of Australia explores whether different formulations of alcohol-based hand rubs “may enhance user acceptability.”[1] This line of inquiry is based on clinical findings showing that people may be more unlikely to use formulations that they dislike.[2]

The types of alcohol-based hand-rubs studied were liquid, foam, and gel, all produced by the same German manufacturer.

What matters?

The nine characteristics of the sanitizers that participants were asked to assess were its application, colour, drying effect, drying speed, ease of product, irritation, satisfaction, smell, and texture. As you can see in this chart, the greatest areas of perceived difference between liquid, foam, and gel are their drying effect, drying speed, and texture:

Overall, the participants found “liquid to be significantly more pleasant than gel; liquid to dry significantly faster than gel; liquid to have significantly more drying effect in the skin than both gel and foam; both gel and foam to be significantly stickier than liquid, and gel to be significantly stickier than foam.”[3]

The result is that 50% of participants choose the liquid formulation as their first choice, followed by 30% for foam, and 20% for gel.[4]

Listening to the user

Seventy-six percent of participants said that the actual composition of the formulation “impacts their level of [hand hygiene] compliance.”[5] The researchers noted how this study might be particularly interested for those in product development—especially in markets like North America where gel is used overwhelming and liquid sanitizer has had a smaller market-share.

Sanitizer formulation at OPHARDT
Study results

Further research possibilities

For this study, participants were told to look away or close their eyes during the application process. There are advantages of doing a blind study. It reduces pre-existing biases. It could be worthwhile, though, to run this same test without blindfolded participants so that we can see whether the aesthetic qualities of liquid, foam, or gel contribute to the overall experience. Hand hygiene is, for many, a visual process, as well as a sensory one.

Another area worth exploring is whether these study results can be universalized. As mentioned before, different markets are using liquid, foam, or gel as their primary sanitizer formulation. Would these study results from Australia be different if we recreated the test in North America? A global study of formulation preferences would be a worthwhile endeavor.

“When designing alcohol formulations and implementing hand hygiene protocols, understanding drivers of preference for formulations may enhance product user acceptability and therefore compliance with hand hygiene.”

Conclusion of the research team

The participants used 3ml of sanitizer for each test. This is the WHO-recommended amount, though people often use less in real world applications. At lower doses, it is possible that the consistency of gel might dry faster and have a more pleasing drying effect. In hospital settings, it is worth considering which formula is most pleasant in 3ml doses.

One piece of the puzzle

The researchers advocate for a multimodal approach to increasing hand hygiene compliance, stating that the type of formulation is not a panacea. [6]

While initiating education, improving access to hygiene hand infrastructure, increasing monitoring and feedback are vital, we cannot lose sight of the user experience. Like football, hand hygiene compliance is a game of inches. No one intervention leads to full compliance, but each improvement that leads to an increase in compliance helps prevent infections.


Sources:

[1] Verwilghen, D., et al. “Identifying Drivers for User Preference and Acceptability of Different Hydro-Alcoholic Hand Rub Formulations.” Journal of Hospital Infection, vol. 117, Nov. 2021, pp. 17–22, 10.1016/j.jhin.2021.08.007. Accessed 16 Nov. 2021.

[2] Verwilghen, D., et al.

[3] Verwilghen, D., et al.

[4] Verwilghen, D., et al.

[5] Verwilghen, D., et al, p. 21.

[6] Verwilghen, D., et al, p. 18.

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