Exploring Surrogate Selection for Virucidal Aerosol Testing: A Qualitative Analysis

The COVID-19 pandemic heightened interest in the development and testing of virucidal chemistries and technologies for use in indoor environments. Direct testing of pathogens often requires a high-level biosafety containment, which can restrict performance evaluations to smaller scales that may have limited translatability to the complexities of real-world indoor environments. Therefore, using viral surrogates that are safer to work with than target pathogens offers many potential benefits, including aerosol testing in more realistic conditions. This scoping review analyzes surrogate selection and use across aerosol, surface, and suspension-based tests and identifies bridges in surrogate selection considerations. A qualitative analysis of 133 studies was conducted to highlight trends, knowledge gaps, and future directions toward standardized surrogate selection frameworks. This review finds that Enterobacteria phage MS2 (MS2) and other bacteriophages are commonly used due to their practicality and safety. There are limited examples of concurrent pathogen and surrogate testing to assess suitability, which is highly context-dependent on the test conditions. Beyond virucide testing, the surrogate selection considerations discussed herein are informative for research on the persistence, transmission, transport, behavior, and nonchemical management of airborne viruses.