Comparative efficacy of commercially available alcohol-based hand rubs and World Health Organization-recommended hand rubs

Antiviral and antibacterial activity of hand sanitizer and surface disinfectant formulations

Emergent diseases caused by viral and bacterial infections have proven to be a current and future challenge. The occurrence of these diseases is usually accompanied by the lack of vaccines and dedicated therapies leaving prevention as the best strategy to adopt. In that context, and apart from confinement and physical distancing measures, an increase in hygiene actions, namely hand and surface cleaning and disinfection can reduce the infection spread originated from our day-to-day routines. However, during crisis situations the high disinfectants demand can very likely lead to having them running out of stock. This impels many individuals and companies to produce their own disinfectants. Here, we explore the main components of a disinfection formulation, both for hand-rub and surface cleaning. Alcohol and non-alcohol based formulations are described, including the possibility to fine tune the properties of the final product in order to increase public acceptance while maintaining product efficacy. The action mechanisms of the main active principles are also described conjugating information from experimental and theoretical data. Overall, the main aspects to develop a disinfectant formulation are addressed, as well as their function, helping formulation developers to better understand the impact of their choices.

Hydrogels in Hand Sanitizers

Hand hygiene can be considered a strategic key useful in the containment of infections such as COVID-19 both at home and in communities because it can dramatically reduce the widespread outbreak of infections. In case of the unavailability of soap and water, "instant" hand sanitizers are recommended because their application can be considered easy, versatile, quick and often less aggressive for the skin. For these reasons, alcoholic and alcohol-free hand rub gels can be considered the best performing formulations on the market. Together with disinfectants and antiseptic agents, hydrogels play a fundamental role in obtaining stable formulations and are easy to disperse, with a pleasant skin feel and an overall good performance. Several compounds commonly used in the pharmaceutical, cosmetic and food industry are available for this purpose, in particular, cellulose derivatives and synthetic polymers derivatives. Each of them is available in several grades, presenting different thickening behavior, rheological properties and compatibility with other ingredients, alcohols in particular. For all these reasons, it is important to explore hydrogel properties and behaviors in different contexts (i.e., hydroalcoholic and aqueous media) in order to develop new and performing hand rub gels, always taking into account the different international legal frameworks regarding disinfectant and sanitizing formulations.

Hand sanitisers amid CoViD-19: A critical review of alcohol-based products on the market and formulation approaches to respond to increasing demand

The world is facing a medical crisis amid the CoViD-19 pandemic and the role of adequate hygiene and hand sanitisers is inevitable in controlling the spread of infection in public places and healthcare institutions. There has been a great surge in demand for hand sanitisation products leading to shortages in their supply. A consequent increase of substandard products in the market has raised safety concerns. This article, therefore, presents a critical review of hand sanitation approaches and products available on the market in light of the scientific evidence available to date. This review also provides a range of hand sanitisation product formulations, and manufacturing instructions to allow for extemporaneous preparations at the community and hospital pharmacies during this urgent crisis. In addition, this emergent situation is expected to continue, hence hand sanitisers will be in demand for an extended time, and the availability and purchase of substandard products on the market create an ongoing safety concern. Therefore, this article shall also provide various commercial organisations, interested in stepping forward the production and marketing of hand sanitisers, with a guide on the development of products of standardised ingredients and formulations.

Efficacy of disinfectant-impregnated wipes used for surface disinfection in hospitals: a review

Background

"Ready-to-use" disinfecting wipes (also known as pre-impregnated disinfecting wipe) are broadly used in food industry and domestic situations. Their application in hospitals and healthcare centres for decontamination of medical devices and surfaces is steadily increasing because of their convenient implementation in practice and reliable performance. Beside their acceptable compliance and easy application, literature reported the disinfection failure due to the interaction between textile substrate and active ingredients, which can highly increase the risk of an infection outbreak. This review aims to call attention to the wide range of variables affecting the disinfectant-impregnated wipes' (DIWs) disinfection performances in hospitals.

Methods

A systematic literature search based on the five categories i. wipes, ii. disinfectants, iii. Application methods, iv. interaction between wipes and active ingredients and v. wiping strategy which can possibly influence the disinfection effectiveness of DIWs was conducted by Google scholar. Studies regarding the efficacy evaluation of DIWs in clinical applications were also reviewed from the National Centre for Biotechnology Information database.

Results

Variables that impact on the disinfection performance of disinfectant-impregnated wipes in surface disinfection in hospitals were summarised and critically discussed. In addition to the information, current disinfectant-impregnated wipes' decontamination efficacy test standards were reviewed, and different standards exposed some disadvantage in their testing design.

Conclusion

Various parameters contribute to the impact of DIWs disinfection performance in practice. The interaction between disinfectant active ingredients and the wiping materials barricades their broad application in hospitals. More studies of the DIWs' disinfection efficacy in clinical practice are in need. Current standards evaluating the DIWs' efficacy are required to improve for more realistic condition simulation and differentiating between mechanical removal of inoculum from a surface and chemical inactivation of the test microbe.

Back to basics: hand hygiene and isolation

Purpose of review

Hand hygiene and isolation are basic, but very effective, means of preventing the spread of pathogens in healthcare. Although the principle may be straightforward, this review highlights some of the controversies regarding the implementation and efficacy of these interventions.

Recent findings

Hand hygiene compliance is an accepted measure of quality and safety in many countries. The evidence for the efficacy of hand hygiene in directly reducing rates of hospital-acquired infections has strengthened in recent years, particularly in terms of reduced rates of staphylococcal sepsis. Defining the key components of effective implementation strategies and the ideal method(s) of assessing hand hygiene compliance are dependent on a range of factors associated with the healthcare system. Although patient isolation continues to be an important strategy, particularly in outbreaks, it also has some limitations and can be associated with negative effects. Recent detailed molecular epidemiology studies of key healthcare-acquired pathogens have questioned the true efficacy of isolation, alone as an effective method for the routine prevention of disease transmission.

Summary

Hand hygiene and isolation are key components of basic infection control. Recent insights into the benefits, limitations and even adverse effects of these interventions are important for their optimal implementation.

Comparison of 3 in vivo methods for assessment of alcohol-based hand rubs

BACKGROUND

Alcohol-based hand rubs (ABHRs) are the primary method of hand hygiene in health-care settings. ICPs increasingly are assessing ABHR product efficacy data as improved products and test methods are developed. As a result, ICPs need better tools and recommendations for how to assess and compare ABHRs.

METHODS

Two ABHRs (70% ethanol) were tested according to 3 in vivo methods approved by ASTM International: E1174, E2755, and E2784. Log10 reductions were measured after a single test product use and after 10 consecutive uses at an application volume of 2 mL.

RESULTS

The test method used had a significant influence on ABHR efficacy; however, in this study the test product (gel or foam) did not significantly influence efficacy. In addition, for all test methods, log10 reductions obtained after a single application were not predictive of results after 10 applications.

CONCLUSIONS

Choice of test method can significantly influence efficacy results. Therefore, when assessing antimicrobial efficacy data of hand hygiene products, ICPs should pay close attention to the test method used, and ensure that product comparisons are made head to head in the same study using the same test methodology.

Less and less-influence of volume on hand coverage and bactericidal efficacy in hand disinfection

Background

Some manufacturers recommend using 1.1 mL per application of alcohol-based handrubs for effective hand disinfection. However, whether this volume is sufficient to cover both hands, as recommended by the World Health Organization, and fulfills current efficacy standards is unknown. This study aimed to determine hand coverage for three handrubs (two gels based on 70% v/v and 85% w/w ethanol and a foam based on 70% v/v ethanol) applied at various volumes.

Methods

Products were tested at product volumes of 1.1 mL, 2 mL, 2.4 mL as well as 1 and 2 pump dispenser pushes; the foam product was tested in addition at foam volumes of 1.1 mL, 2 mL, and 2.4 mL. Products were supplemented with a fluorescent dye and 15 participants applied products using responsible application techniques without any specific steps but the aim of completely covering both hands. Coverage quality was determined under ultraviolet light by two blinded investigators. Efficacy of the three handrubs was determined according to ASTM E 1174-06 and ASTM E 2755-10. For each experiment, the hands of 12 participants were contaminated with Serratia marcescens and the products applied as recommended (1.1 mL for 70% v/v ethanol products; 2 mL for the 85% w/w ethanol product). Log₁₀-reduction was calculated.

Results

Volumes < 2 mL yielded high rates of incomplete coverage (67%–87%) whereas volumes ≥ 2 mL gave lower rates (13%–53%). Differences in coverage were significant between the five volumes tested for all handrubs (p < 0.001; two-way ANOVA) but not between the three handrubs themselves (p = 0.796). Application of 1.1 mL of 70% v/v ethanol rubs reduced contamination by 1.85 log₁₀ or 1.60 log₁₀ (ASTM E 1174-06); this failed the US FDA efficacy requirement of at least 2 log₁₀. Application of 2 mL of the 85% w/w ethanol rub reduced contamination by 2.06 log₁₀ (ASTM E 1174-06), fulfilling the US FDA efficacy requirement. Similar results were obtained according to ASTM E 2755-10.

Conclusions

Our data indicated that handrubs based on 70% ethanol (v/v) with a recommended volume of 1.1 mL per application do not ensure complete coverage of both hands and do not achieve current ASTM efficacy standards.