Aerosol stability of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2)

Abstract

The routes of transmission of the zoonotic pathogen severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been extensively studied to understand the spread at individual and population levels. Aerosol particles produced by infected individuals and the deposition patterns inhaled are known to affect the virulence of bioaerosol pathogens. Droplet nuclei particles (< 5 microns) aerosols typically deposit within the alveolar spaces of the lungs, whereas droplet (>5 microns) aerosols typically deposit within the nasopharyngeal and tracheobronchial regions of the respiratory tract. A few studies have evaluated pulmonary disease following droplet nuclei size particles of SARS-CoV-2 aerosol inhalation in African green monkeys and golden hamsters, concluding that both models have mild respiratory disease representative of human disease. More importantly, human participants with SARS-CoV-2 infections have been studied to look at the generation of particles during breathing, talking, and singing; the study concluded droplet nuclei particles accounted for 85% of the copies of virus produced and play a significant role in transmission. However, the environmental persistence of the aerosolized droplet nuclei particles, and the likely role of environmental persistence in driving transmission, is unknown for SARS-CoV-2. In these studies, we show the changing aerosol stability of SARS-CoV-2 during the supplanting waves of Variants of Concern (VOC). With the determination of viable viral particles characterized over time, we can make inferences about the role VOC and aerosol transmission have in driving population-level pathogen transmission. A secondary objective of these studies was to characterize the role those evolving mutations have had on viral entry and aerosol durability. Our work suggests that aerosol stability may be important in driving some population-level phenomena (e.g., indoor transmission, including superspreader events) but given the short infected-to-naive transmission transit time, the variation in the duration of aerosol stability among VOCs may not explain the difference in transmission rates of VOCs. This data will be useful for assessing the future evolution of aerosol transmission of SARS-CoV-2.