Activity of an alcohol-based hand gel against human adeno-, rhino-, and rotaviruses using the fingerpad method

Abstract

Objective: To assess the activity against three non-enveloped viruses (an adeno-, a rhino- and a rotavirus) of a gel containing 60% ethanol, using experimentally contaminated thumb- and fingerpads of 12 panelists, as per standard procedure E-1838-96 of the American Society of Testing and Materials.

Design: Each digit received 10 microL of the test virus suspension. The inoculum from the thumbs was eluted immediately with 990 microL of Earle's balanced salt solution (EBSS) to assess the amount of virus on each digit (0-minute control). The inoculum on the fingers was allowed to dry (20-25 minutes), and virus was eluted from two fingerpads to determine the loss in virus infectivity upon drying (baseline titer). Then the dried inoculum on randomly selected fingers was exposed to 1 mL of the test product or standard hard water (200-ppm calcium carbonate) for 20 seconds. The virus remaining was eluted with 1 mL of EBSS, titrated to determine the amounts eliminated, and compared to the baseline titer.

Results: Each digit received at least 10(4) plaque-forming units of virus in 10 microL. The amounts of adeno-, rhino-, and rotaviruses surviving the drying were 30%, 75%, and 42%, respectively. The product reduced the infectivity titers of the three viruses by 3 to >4 log10 when compared to a reduction of < or =1 log10 for the hard-water rinse.

Conclusion: The level of virus reduction by gel was statistically significantly higher than that seen with the water control. Evidence for such activity against non-enveloped viruses supports further investigation of the benefits of this product.