Evaluating Residual Antimicrobial Coatings Test Results

EPA researchers are building on an expansive body of world-class research by applying that knowledge to reduce the risk of exposure to SARS-CoV-2, the virus that causes COVID-19. This research will help inform the strategies that state, tribal, local, and territorial governments and other stakeholders use to reduce the risk of exposure to SARS-CoV-2.  

Antimicrobial pesticides are intended to disinfect, sanitize, reduce, or mitigate growth or development of microbiological organisms (e.g., bacteria, viruses, fungi) on inanimate objects. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), a pesticide must be registered by EPA before it can be legally sold or distributed in the United States. Once registered, pesticides must be used in a manner consistent with the approved label directions and claims.

Surfaces can be sources of exposure to viruses and present a potential route for transmission of disease. Infectious virus can be transferred to people and other objects by direct contact with surfaces; contamination on hands can then be spread to the mouth, nose or eyes and can cause infection. In the current COVID-19 pandemic, SARS-CoV-2 has been shown to survive on surfaces such as stainless steel for a period of hours to days. Survival, often reported as half-life (time it takes to reduce the viable virus population by 50%), is a function of material type and environmental conditions. Viral persistence tends to increase at cooler conditions and on porous or semi-porous surfaces. To reduce potential transmission from surfaces, the U.S. Centers for Disease Control and Prevention (CDC) recommends frequent hand washing and cleaning and disinfecting surfaces with approved disinfectants against SARS-CoV-2. EPA maintains a list of approved disinfectants for use against SARS-CoV-2 on surfaces.

EPA and CDC recommend regular cleaning and disinfection of frequently touched surfaces. For example, door handles and handrails in public spaces are often touched frequently throughout each day. However, in many public places, cleaning and disinfecting these surfaces at a frequency to effectively reduce potential transmission is not feasible.

Products that reduce or eliminate antimicrobials for extended durations after application may help to reduce potential exposure to viruses on frequently touched surfaces. However, EPA has not evaluated the efficacy of any registered products claiming long-lasting (e.g., days to weeks) efficacy against viruses. Therefore, there are currently no EPA-registered products eligible to make claims that they are effective against SARS-CoV-2 over the course of days to months (i.e., “long lasting” efficacy claims). Several products are registered with EPA for the purposes of reducing or eliminating odor- and stain-causing bacteria and fungi on surfaces. They are not registered for effectiveness against viruses. In some cases, manufacturers and distributors of these “microbiostat” products are asserting they reduce or eliminate viruses on surfaces for extended periods after application. To date, these products have not been registered with EPA as antiviral coatings; some are currently being used, both domestically and internationally, in combination with cleaning and disinfection methods.  The overall benefit of using such products in reducing the potential exposure from surfaces, such as in mass transit systems, is not yet understood or recognized by EPA.

The objective of this project is to evaluate antimicrobial products as long-lasting antimicrobials in laboratory testing – assessing their efficacy at reducing infectious virus recovery from surfaces that have been coated with the products. The evaluation will include assessment of effectiveness of products as a function of time after their application, and the potential impact of normal use (including cleaning and wear or abrasion) and varying environmental conditions (e.g., temperature, humidity) over that time.

The study may identify products that demonstrate residual (e.g., hours) and long-lasting (e.g., days to weeks) efficacy against viruses on surfaces. The results of this research do not supplant data required for product registration nor for adding additional clams to product labels. Products must be used in accordance with their label claims under FIFRA. EPA does not endorse the use of any products tested in this study. 

EPA is conducting several studies to inform the response to the COVID-19 public health emergency. The summary here is intended to provide a simple representation of the results of on-going testing; therefore, only a brief description of the purpose of the study, methods, and interim results are provided.  This study is being conducted in accordance with an approved Quality Assurance Project Plan. The interim results have been reviewed by internal EPA technical experts, quality assurance staff, and management. No interpretation of the interim results is provided. Once complete, the study and its results will be described in detail in a publication subjected to external, expert peer review. EPA does not endorse the purchase or sale of any commercial products or services.