Clean Airplane Program – Live Virus Validation Testing Rohit R. Nene, Bryan D. Moran, Daniel R. Roberson, Nathan T. Braaten Contents Abstract ...................................................................................................................................................... 1 Introduction ............................................................................................................................................... 2 Test Procedures ....................................................................................................................................... 3 Mockup Testing .......................................................................................................................................... 3 Airplane Testing .......................................................................................................................................... 5 University of Arizona Lab Testing ............................................................................................................ 7 Results ........................................................................................................................................................ 7 Conclusions............................................................................................................................................. 11 Limitations and Future Research ...................................................................................................... 12 Appendix .................................................................................................................................................. 13 Sources ..................................................................................................................................................... 20 Abstract The COVID-19 global pandemic has significantly encumbered many industries including air travel and aviation, with drastically fewer travelers flying today than in the past several years. In an effort to enhance safety and restore confidence in air travel, Boeing’s Clean Airplane Program undertook studies to validate the efficacy of various disinfection technologies intended to combat SARS-CoV-2 – the virus that causes COVID-19 – on commercial aircraft cabin surfaces. Disinfection technologies included disinfectant wiping, antimicrobial coatings, ultraviolet light, and electrostatic sprayers. While transmission of SARS-CoV-2 through contact from surfaces may be a less common infection pathway1, successful disinfection technologies applied to high-touch surfaces remain an important cornerstone to the enhancement of the safety and comfort of passengers, crew, and personnel on commercial aircraft. This paper discusses these various disinfection technologies and reviews the results from validation testing conducted by Boeing and the University of Arizona. Validation testing was performed in an airplane interior mockup, a production airplane, and laboratory settings, using both surrogate viruses, bacteriophage MS2 and human coronavirus HCoV-229E, and the novel human coronavirus SARS-CoV-2. MS2 was evaluated in an interior mockup and production airplane at Boeing’s facilities. MS2, HCoV-229E and SARS-CoV-2 were evaluated in controlled laboratory environments by the University of Arizona. Results show that the airplane environment can be effectively disinfected with appropriate methods. Variations in results are seen with treatment, application and to some degree, surface 1 Copyright © 2020 Boeing. All rights reserved. materials. Disinfectant wiping is shown to be highly effective with greater than 4 log10 (> 99.99%) reduction against HCoV-229E. Several antimicrobial coatings show close to 4 log10 (99.99%) reduction against HCoV-229 in just 30 minutes, and Boeing prototype polymer P13 showed nearly 4 log10 (99.99%) reduction in 30 minutes and nearly 5 log10 (99.999%) in 60 minutes against SARS-CoV-2. Ultraviolet light (UV-C, 222 nm) technology is shown to be highly effective against MS2 and HCoV-229E with greater than 2 log10 (99%) or 3 log10 (99.9%) reduction being achievable at appropriate energy dose levels. Electrostatic sprayer application using chemical disinfectant Calla 1452 followed by a quick cloth wipe showed greater than 2 log10 (99%) reduction against HCoV-229E. The test results show that these technologies and applications are highly effective in eliminating key viruses on representative aircraft surfaces. While MS2 and HCoV-229E are similar to SARS-CoV-2, additional data using SARS-CoV-2 will confirm the efficacy of these treatments further and draw even stronger conclusions. Introduction The advent of the COVID-19 global pandemic has significantly impacted global, regional and domestic air travel. At the time of this writing, the United States Transportation Security Administration (TSA) checkpoint traveler numbers for 2020 and 20192 show passenger traffic has reduced to between 30% and 40% of the levels it was a year ago during the same week with the lowest levels close to 4% during mid-April 2020. This has spurred an imperative across the air travel industry to enhance protections at multiple stages of the travel journey to minimize health risks to travelers, airport staff, ground crew, airline personnel, and to restore confidence in air travel. Boeing’s Clean Airplane Program and Validation Testing efforts focus on enhancing protections in the airplane cabin, flight deck and cargo compartments using products, technologies and methods for cleaning and disinfection. While many of the products, technologies and methods have been previously evaluated in laboratory environments, it is essential to validate the efficacy of these in representative mockup and production airplane environments, allowing Boeing to make the best cleaning and disinfecting recommendations to the airlines. The disinfection technologies considered under Boeing’s Clean Airplane Program – disinfectants, antimicrobial coatings, ultraviolet light, and electrostatic sprayers – were chosen based on known or anticipated efficacy against SARS-CoV-2, equivalent viruses or pathogens, and the range of methods by which they can be applied to commercial aircraft surfaces. Disinfectants are expected to be effective according to the Environmental Protection Agency’s (EPA) List N3 and require manual application. The compatibility and limitations of selected disinfectants on aircraft materials and components4 were also considered. Antimicrobial coatings offer persistent protection on surfaces, and require initial application followed by periodic reapplication. Electrostatic sprayers provide a way to disinfect large surface areas of the aircraft cabin consistently and efficiently5. Finally, ultraviolet light (UV-C, 222 nm) provides an effective treatment against viruses without the damaging effect on skin or eyes6, and can cover many surfaces rapidly within an aircraft. Boeing partnered with the University of Arizona to validate the efficacy of various disinfection technology solutions and to authenticate the test preparation, procedures and results. Dr. Charles Gerba, Professor of Environmental Science at the University of Arizona, was the principal investigator in this partnership and is a leading academic figure in virology, known for his methodologies in pathogen detection in food and water, and pathogen occurrence in households and risk assessment7. The studies undertaken were conducted in an airplane interior mockup and 2 Copyright © 2020 Boeing. All rights reserved. production airplane using the surrogate virus MS2, and later in laboratory settings using MS2, human coronavirus HCoV-229E and the novel human coronavirus SARS-CoV-2. The surrogate virus MS2 has a long and proven history of use in applications since the 1980s as tracers in groundwater8, waste/water treatment plants, and in academic studies to trace movement of pathogenic viruses in offices, hotels, health care facilities, and hospitals. MS2, a non-enveloped virus, is also a common viral surrogate for Norovirus and Rhinovirus, known for causing gastroenteritis and the common cold, respectively. MS2 is easy to work with, harmless to humans, and shares many features with eukaryotic viruses9, which have genetic material contained in an enveloped nucleus. MS2 can be grown to high levels allowing easier determination for amount of viral reduction10. While MS2 exhibits behavior similar to SARS-CoV- 2 in some regards, it is also known to be more robust and resistant than SARS-CoV-2. As such, it is expected that these technology solutions will have a higher likelihood of killing HCoV-229E and SARS-CoV-2, both enveloped viruses, in comparison to MS2. In July 2020, testing was conducted in a representative Boeing 787 cabin interior mockup at the Aircraft Integration Center (AIC) in Everett, Washington and on a Boeing 737 production airplane interior at Boeing Field in Seattle, Washington. The efficacy of disinfectants, antimicrobial coatings, electrostatic sprayers and ultraviolet light was evaluated on various high-touch cabin surfaces such as armrests, bins, lavatories, seats, tray tables, window buttons, and galleys. Subsequent testing carried out at the University of Arizona’s Water & Energy Sustainable Technology (WEST) Center facility in Tucson, Arizona helped corroborate the testing performed at Boeing and confirmed efficacy against SARS-CoV-2. Test Procedures Mockup Testing Mockup testing was conducted in a representative Boeing 787 cabin interior at the Aircraft Collaboration