Anatomy

Internal medicine

Pathology

Pathological

Virus

Hamster

Disease

Respiratory tract

Upper respiratory tract infection

Coronavirus disease 2019 (COVID-19)

Infectious disease (medical specialty)

Biology

Molecular biology

Virology

Immunology

Lung

Respiratory tract infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Respiratory system

Medicine

Nature Communications

Since its discovery in 2019, multiple variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been identified. This study investigates virus spread and associated pathology in the upper and lower respiratory tracts of Syrian golden hamsters at 4 days post intranasal SARS-CoV-2 Omicron infection, in comparison to infection with variants of concern (VOCs) Gamma and Delta as well as ancestral strain 614 G. Pathological changes in the upper and lower respiratory tract of VOC Omicron infected hamsters are milder than those caused by other investigated strains. VOC Omicron infection causes a mild rhinitis with little involvement of the olfactory epithelium and minimal lesions in the lung, with frequent sparing of the alveolar compartment. Similarly, viral antigen, RNA and infectious virus titers are lower in respiratory tissues of VOC Omicron infected hamsters. These findings demonstrate that the variant has a decreased pathogenicity for the upper and lower respiratory tract of hamsters.

SARS-CoV-2 Omicron variant causes mild pathology in the upper and lower respiratory tract of hamsters