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Persistence of Phi6, a SARS-CoV-2 surrogate, in simulated indoor environments: Effects of humidity and material
Eloise Parry-Nweye1, Zhenlei Liu2, Yousr Dhaouadi1
1Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America.
Abstract:
The SARS-CoV-2 virus caused the COVID-19 pandemic and brought major challenges to public health. It is transmitted via aerosols, droplets, and fomites. Among these, viral transmission through fomites is not well understood although it remains a very important transmission route. This motivated us to study how fomites play a role in viral transmission within controlled indoor environments. To achieve this, we investigated viral aerosol persistence on fomites under different humidity levels to mimic the built environment. We developed a protocol to study the effect of humidity on viral infectivity using a full-scale environmental chamber. The results show that the infectivity of aerosolized Phi6 in air decreased by ≥ 1 log10 as the relative humidity (RH) increased from 25% to 75% but then increased by ≥ 1 log10 as the RH further increased to 85%, resulting in a characteristic V-shape curve which varied with exposure time. Consistently, we show that although material properties may impact viral persistence, changes in the local humidity more significantly influence viral persistence on fomites. These results provide new insights into indoor fomite-mediated viral transmission under different environmental conditions. These findings will help guide the design of more effective strategies for viral control in indoor environments.
Insights
Viral infectivity on fomites significantly changes with humidity, decreasing as relative humidity (RH) rises to 75% then increasing at 85%. This V-shape curve impacts indoor viral transmission control strategies.
Area of Science:
- Environmental Science
- Microbiology
- Public Health
Background:
- SARS-CoV-2 transmission occurs via aerosols, droplets, and fomites.
- Fomite-mediated viral transmission, especially indoors, requires further understanding.
- Controlled indoor environments are crucial for studying viral persistence.
Purpose of the Study:
- Investigate the role of fomites in viral transmission within indoor environments.
- Determine the effect of varying humidity levels on viral aerosol persistence on fomites.
- Understand how environmental conditions influence viral infectivity and transmission routes.
Main Methods:
- Developed a protocol using a full-scale environmental chamber to study viral persistence.
- Investigated aerosolized Phi6 virus infectivity under different relative humidity (RH) levels (25% to 85%).
- Assessed viral persistence on fomites, considering material properties and local humidity.
Main Results:
- Viral infectivity showed a V-shape curve with increasing RH, decreasing from 25% to 75% and increasing from 75% to 85%.
- Changes in local humidity had a more significant impact on viral persistence than material properties.
- Viral aerosol persistence on fomites varied with exposure time and RH levels.
Conclusions:
- Humidity significantly influences viral persistence on fomites, impacting indoor transmission dynamics.
- Findings provide insights into fomite-mediated viral transmission under diverse environmental conditions.
- Results can inform the development of effective viral control strategies for indoor spaces.
