Impact of different hand drying methods on surrounding environment: aerosolization of virus and bacteria and transference to surfaces.

BACKGROUND: In recent years, hand drying has been highlighted as a key step in appropriate hand hygiene (WHO 2009), as moisture on hands can increase transference of microorganisms from hands to surfaces and vice-versa.

AIM: To understand bacterial and viral aerosolization following hand drying and study transference of microorganisms from hands to surfaces after drying using different methods.

METHODS: Groups of five volunteers had their hands pre-washed with soap, rinsed and dried then inoculated with a concentrated mixture of Pseudomonas fluorescens and MS2 bacteriophage. Volunteers entered, one at a time, an empty washroom and rinsed or washed (with soap) their hands prior to drying with a jet dryer or paper towels. Each volunteer also applied one hand successively to various surfaces, while their other hand was sampled using the glove juice method. Both residual bacteria and viruses were then quantified from the washroom air, surface swabs and hand samples.

FINDINGS: Results showed P. fluorescens and MS2 bacteriophages were rarely aerosolized while drying hands, for any of the drying methods studied. Results also showed limited, and similar, transference of both microorganisms studied onto surfaces, for all drying methods used in this work.

CONCLUSION: The use of jet dryers or paper towels produce low levels of aerosolization while drying hands in a washroom. Similarly, both drying methods result in low transference to surfaces. While the COVID-19 pandemic raised concerns regarding public washroom, this study shows that all methods tested are hygienic solutions to dry washed hands.