Gas Composition and Humidity Affect the Stability of Enveloped Viruses
ALEXANDRA LONGEST, Rania Smeltz, Nisha Duggal, Linsey Marr,
Virginia Tech Abstract Number: 29
Working Group: Aerosol Science of Infectious Diseases: Lessons and Open Questions on Models, Transmission and Mitigation
AbstractRespiratory viruses, such as influenza, RSV, and SARS-CoV-2, spread through the air and cause major strain on medical systems throughout the world. Research has shown that environmental stability of these viruses in aerosols and droplets can be influenced by many factors, including temperature, relative humidity, physico-chemical properties of droplets, and virus strain, but the mechanism of inactivation of viruses is unknown. One hypothesis is that a change in pH in the droplets, due to CO2 or other trace gases in the atmosphere, damages the virus. Another is that reactive oxygen species in the air partition into droplets and cause damage. The objective of this study was to determine the effect of different atmospheres (ambient air versus nitrogen) and RH (27, 55, and 82%) on the stability of two enveloped viruses: bacteriophage Phi6 and influenza A virus in 1 µL droplets over 4 hours. Phi6 was a surrogate used first to establish methodology and preliminary results. At low RH, there was no difference in decay between atmospheres. At mid and high RHs, there was significantly more decay at certain times (2,4 and 4 hours, respectively) in ambient air versus nitrogen. This experiment has been extended to a seasonal influenza virus (H1N1pdm09). Overall, this study suggests that the composition of the surrounding gas affects inactivation of viruses in droplets, and that droplet evaporation, mediated by RH, has an impact as well. Understanding the drivers of virus inactivation is important in developing interventions for reducing transmission of respiratory viruses.