ASTM E2721–16. Evaluation of Effectiveness of Decontamination Procedures for Surfaces When Challenged with Droplets Containing Human Pathogenic Viruses.

Several viruses can spread to health personnel or other people from contaminated surfaces of a wide variety of objects. The patients can contaminate with their secretions the surfaces and objects of common use, such as telephones, doorknobs, computers, light switches, stair rails, desks, or tables, among others. Some viruses can survive for some time outside a host organism, so it is recommended to insist on hygienic practices as a preventive measure.

This method aims to evaluate the effectiveness of decontamination procedures for surfaces exposed to splashes that may contain pathogenic viruses. In the method, defined procedures are used to generate aerosol droplets that simulate the human secretions produced by the respiratory tract, with special emphasis on the droplet size distribution and the procedures used to generate the aerosols. The method is designed for influenza viruses but can be adapted to be performed with other types of respiratory viruses or substitutes for them. In addition, it is suitable for working with a wide variety of environmental surfaces.

The method does not use a liquid inoculum to contaminate the surface, but applies the virus through the dispersion of droplets, representative of human respiratory secretions. The droplets have a size of 1.56 mm and are created by an specific equipment. The proper distribution of the droplets in the test samples is achieved by rotating the samples to be tested on a turntable at 3 rpm. The procedure for decontaminating the surface will be done before the droplets have completely dried. The assay is carried out in triplicate together with the controls.

The effectiveness of decontamination is determined by comparing the amount of viable virus recovered in the treated and untreated test sample, reporting the logarithmic reduction obtained. There are no specific approval or rejection criteria for this method, but its objective is only to quantify the effectiveness of decontamination methods.

The client must choose a contact time, a test temperature and humidity and provide the decontamination conditions that are to be carried in the test.