SARS-CoV-2 Omicron Induces Enhanced Mucosal Interferon Response Compared to other Variants of Concern, Associated with Restricted Replication in Human Lung Tissues.

SARS-CoV-2 Omicron variant has been characterized by decreased clinical severity, raising the question of whether early variant-specific interactions within the mucosal surfaces of the respiratory tract could mediate its attenuated pathogenicity. Here, we employed ex vivo infection of native human nasal and lung tissues to investigate the local-mucosal susceptibility and innate immune response to Omicron compared to Delta and earlier SARS-CoV-2 variants of concern (VOC). We show that the replication of Omicron in lung tissues is highly restricted compared to other VOC, whereas it remains relatively unchanged in nasal tissues. Mechanistically, Omicron induced a much stronger antiviral interferon response in infected tissues compared to Delta and earlier VOC-a difference, which was most striking in the lung tissues, where the innate immune response to all other SARS-CoV-2 VOC was blunted. Notably, blocking the innate immune signaling restored Omicron replication in the lung tissues. Our data provide new insights to the reduced lung involvement and clinical severity of Omicron.

Evaluating the change in patterns of traumatic injury in the setting of pandemic and social distancing restrictions: An analysis of a level 1 trauma center.

BACKGROUND: Social distancing measures and quarantine during the COVID-19 pandemic have led to reported changes in traumatic injury patterns. We set to examine the effects of these restrictive guidelines in our trauma center. METHODS: This is a retrospective chart review of all patients evaluated for traumatic injuries at a Level 1 trauma center during two time periods: March-June 2020 (COVID) and March-June 2019 (Pre-COVID). RESULTS: Overall trauma volume did not differ significantly between the two time periods. Changes seen during COVID included increases in penetrating injuries (12.5% vs 6.7%, p < 0.001), particularly those due to firearms (7.5% vs 3.7%, p < 0.001). Hospital length of stay, intensive care unit length of stay, and days on the ventilator remained consistent between the two groups. Trends toward increased injuries in the home and non-accidental trauma were not statistically significant. CONCLUSION: Traumatic injury patterns have changed as a result of social distancing in both the adult and pediatric trauma populations. Analyzing the effects of social distancing on trauma can lead to a better development of preventive strategies.