Virus transfer at the skin-liquid interface

Understanding virus transfer between liquid and skin is necessary to estimate transmission during water-related activities. In the present study, we modeled virus transfer from liquid-to-skin and skin-to-liquid. Specifically, we performed human subject studies using unenveloped (MS2, Qβ) and enveloped (Φ6) bacteriophage as pathogenic virus surrogates. Our study shows that transfer from liquid-to-skin is describable by a single, universal model based on 1) virus concentration and 2) volume of liquid remaining on skin. Liquid conditions (pH 6-9, ionic strength 10 - 550 mM), contact times (0.1 - 30 min), and virus species had little to no influence on virus transfer. The model accounts for both; virus adsorbed onto the skin and virus in the liquid retained on skin. In comparison, virus transfer from skin-to-liquid was influenced by the wetness of the skin and by liquid type (water, saliva). Up to 90±19% of the virus inoculated on the skin are transferred to the water when the skin remains wet, compared to and 30 ± 17% when is dry. The transfer from skin-to-liquid was 41% higher when the recipient liquid was water as compared with saliva. This study quantifies virus transfer between liquid and skin, identifies factors influencing transfer, and guides risk assessments of water-related activities.