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

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 Overall design: Hamster lung samples infected with SARS-CoV-2 1 day or 4 days after infection comparing routes of infection; arerosol, formite, intranasal, plus control. 29 samples total, 3 to 4 replicates per condition.

严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）可通过接触传播、污染物（fomite）传播和气溶胶传播实现扩散，目前不同传播途径的相对贡献仍存在广泛争议。本研究证实，叙利亚仓鼠（Syrian hamster）可经鼻内暴露、气溶胶暴露及污染物暴露感染该病毒。不同暴露途径会引发截然不同的疾病表型：鼻内接种与气溶胶接种可导致严重的呼吸系统病理损伤、更高的病毒载量（virus load）以及更显著的体重丢失；与之相反，污染物暴露引发的疾病表型更为温和，以抗炎免疫状态和延迟的病毒脱落（virus shedding）模式为特征。尽管呼吸道病毒脱落的整体总量与疾病严重程度无关，但脱落的起始时间却与严重程度密切相关：早期病毒脱落与疾病严重程度升高存在关联。气溶胶传播的效率高于污染物传播，且受气流方向调控。鉴于SARS-CoV-2仍在持续进化，经过严格表征的SARS-CoV-2传播模型对于评估其传播能力和致病潜力的潜在变化至关重要。实验设计：采集感染后1天或4天的SARS-CoV-2感染仓鼠肺组织样本，对比不同感染途径（气溶胶（aerosol）、污染物（fomite）、鼻内接种及对照组）。本实验共包含29个样本，每组设置3至4个生物学重复。