Endogenous interferon-beta but not interferon-alpha or interferon-lambda levels in upper respiratory tract predict clinical outcome in critical COVID-19 patients independent of viral load (preprint)

Although the subject of intensive preclinical and clinical research, controversy on the protective vs. deleterious effect of interferon (IFN) in COVID-19 remains. Some apparently conflicting results are likely due to the intricacy of IFN subtypes (type I: IFN-alpha/beta, type III: IFN-lambda), timing and mode of administration (nebulized/subcutaneous) and clinical groups targeted (asymptomatic/mild, moderate, severe/critical COVID-19). Within the COntAGIouS (COvid-19 Advanced Genetic and Immunologic Sampling) clinical trial, we investigated endogenous type I and type III IFNs in nasal mucosa as possible predictors of clinical outcome in critical patients, as well as their correlation to SARS-CoV-2 viral load, using nCounter technology. We found that endogenous IFN-beta expression in the nasal mucosa predicts clinical outcome, independent of viral replication or Apache II score, and should be considered as a prognostic tool in a precision medicine approach of IFN therapy in COVID-19 clinical management.

Mechanical ventilation affects respiratory microbiome of COVID-19 patients and its interactions with the host (preprint)

Understanding the pathology of COVID-19 is a global research priority. Early evidence suggests that the microbiome may be playing a role in disease progression, yet current studies report contradictory results. Here, we examine potential confounders in COVID-19 microbiome studies by analyzing the upper (n=58) and lower (n=35) respiratory tract microbiome in well-phenotyped COVID-19 patients and controls combining microbiome sequencing, viral load determination, and immunoprofiling. We found that time in the intensive care unit and the type of oxygen support explained the most variation within the upper respiratory tract microbiome, dwarfing (non-significant) effects from viral load, disease severity, and immune status. Specifically, mechanical ventilation was linked to altered community structure, lower species- and higher strain-level diversity, and significant shifts in oral taxa previously associated with COVID-19. Single-cell transcriptomic analysis of the lower respiratory tract of ventilated COVID-19 patients identified increased oral microbiota compared to controls. These oral microbiota were found physically associated with proinflammatory immune cells, which showed higher levels of inflammatory markers. Overall, our findings suggest confounders are driving contradictory results in current COVID-19 microbiome studies and careful attention needs to be paid to ICU stay and type of oxygen support, as bacteria favored in these conditions may contribute to the inflammatory phenotypes observed in severe COVID-19 patients.