Persistence of Phi6, a SARS-CoV-2 Surrogate, in Simulated Indoor Environments: Effects of Humidity and Material Moisture Adsorption
ELOISE PARRY-NWEYE, Zhenlei Liu, Yousr Dhaouadi, Xin Guo, Jianshun Zhang, Dacheng Ren,
Syracuse University Abstract Number: 36
Working Group: Aerosol Science of Infectious Diseases: Lessons and Open Questions on Models, Transmission and Mitigation
AbstractThe COVID-19 pandemic brought major challenges to public health and is primarily transmitted via aerosols, droplets, and fomites. However, there is a lack of understanding of virus persistence on fomites under different environmental conditions in a realistic environment. Thus, we aimed to bridge this knowledge gap especially as fomites are a significant virus transmission route. This study utilized
Phi6, an 85 nm enveloped dsRNA bacteria virus, as a coronavirus surrogate due to its structural similarities. The experiments were conducted in a full-scale aerobiology chamber to simulate a realistic indoor environment. The viral titers were quantified via plaque assays and Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), which quantify the infective viral load and total viral load respectively. We initially assessed the effect of our sampling methods on the viability and integrity of aerosolized
Phi6 to validate the observed humidity-induced inactivation. Our results show that the infectivity of aerosolized
Phi6 decreases by ≥ 1-log as the Absolute Humidity (AH) increases from 5.6 g.m
-3 to 9.2 g.m
-3 to 17.4 g.m
-3 and then increases by ≥ 1-log as the AH increases to 19.5 g.m
-3. The kinetics of the humidity-induced inactivation shows that the decay rate of infectivity changed in the order (high to low) at 17.4 g.m
-3 > 5.6 g.m
-3 ≈ 9.2 g.m
-3 ≈ 19.5 g.m
-3. Consequently, we show that although material properties may impact virus persistence, however, local humidity at the air-substrate interface more significantly influences virus persistence. In addition, we show postulated changes in the aerosol pH and how these changes would affect the aerosolized virus. These results provide more insights into indoor viral transmission under varied environmental conditions. These findings will help the design of more effective strategies for viral control in indoor environments.