SARS-CoV-2 disease severity and transmission efficiency is increased for airborne compared to fomite exposure in Syrian hamsters

Here, Port and Yinda et al. directly compare the relative contribution of contact, fomite, and airborne transmission route of SARS-CoV-2 to disease outcome in Syrian hamsters; while intranasal and aerosol inoculation causes severe pathogenesis, fomite exposure is characterized by milder disease. Transmission of SARS-CoV-2 is driven by contact, fomite, and airborne transmission. The relative contribution of different transmission routes remains subject to debate. Here, we show Syrian hamsters are susceptible to SARS-CoV-2 infection through intranasal, aerosol and fomite exposure. Different routes of exposure present with distinct disease manifestations. Intranasal and aerosol inoculation causes severe respiratory pathology, higher virus loads and increased weight loss. In contrast, fomite exposure leads to milder disease manifestation characterized by an anti-inflammatory immune state and delayed shedding pattern. Whereas the overall magnitude of respiratory virus shedding is not linked to disease severity, the onset of shedding is. Early shedding is linked to an increase in disease severity. Airborne transmission is more efficient than fomite transmission and dependent on the direction of the airflow. Carefully characterized SARS-CoV-2 transmission models will be crucial to assess potential changes in transmission and pathogenic potential in the light of the ongoing SARS-CoV-2 evolution.

Automated summary

Port and Yinda et al. directly compared the relative contribution of contact, fomite, and airborne transmission routes of SARS-CoV-2 in Syrian hamsters and found that different routes of exposure lead to distinct disease manifestations. Infection through intranasal and aerosol exposure caused severe respiratory pathology, while fomite exposure resulted in milder disease characterized by an anti-inflammatory immune state and delayed shedding pattern.