The local and systemic response to SARS-CoV-2 infection in children and adults

While a substantial proportion of adults infected with SARS-CoV-2 progress to develop severe disease, children rarely manifest respiratory complications. Therefore, understanding differences in the local and systemic response to SARS-CoV-2 infection between children and adults may provide important clues about the pathogenesis of SARS-CoV-2 infection. To address this, we first generated a healthy reference multi-omics single cell data set from children (n=30) in whom we have profiled triple matched samples: nasal and tracheal brushings and PBMCs, where we track the developmental changes for 42 airway and 31 blood cell populations from infancy, through childhood to adolescence. This has revealed the presence of naive B and T lymphocytes in neonates and infants with a unique gene expression signature bearing hallmarks of innate immunity. We then contrast the healthy reference with equivalent data from severe paediatric and adult COVID-19 patients (total n=27), from the same three types of samples: upper and lower airways and blood. We found striking differences: children with COVID-19 as opposed to adults had a higher proportion of innate lymphoid and non-clonally expanded naive T cells in peripheral blood, and a limited interferon-response signature. In the airway epithelium, we found the highest viral load in goblet and ciliated cells and describe a novel inflammatory epithelial cell population. These cells represent a transitional regenerative state between secretory and ciliated cells; they were found in healthy children and were enriched in paediatric and adult COVID-19 patients. Epithelial cells display an antiviral and neutrophil-recruiting gene signature that is weaker in severe paediatric versus adult COVID-19. Our matched blood and airway samples allowed us to study the spatial dynamics of infection. Lastly, we provide a user-friendly interface for this data1 as a highly granular reference for the study of immune responses in airways and blood in children

Local and systemic responses to SARS-CoV-2 infection in children and adults

It is not fully understood why COVID-19 is typically milder in children1–3. To examine differences in response to SARS-CoV-2 infection in children and adults, we analysed paediatric and adult COVID-19 patients and healthy controls (total n=93) using single-cell multi-omic profiling of matched nasal, tracheal, bronchial and blood samples. In healthy paediatric airways, we observed cells already in an interferon-activated state, that upon SARS-CoV-2 infection was further induced especially in airway immune cells. We postulate that higher paediatric innate interferon-responses restrict viral replication and disease progression. The systemic response in children was characterised by increases in naive lymphocytes and a depletion of natural killer cells, while in adults cytotoxic T cells and interferon-stimulated subpopulations were significantly increased. We provide evidence that dendritic cells initiate interferon signaling in early infection, and identify novel epithelial cell states that associate with COVID-19 and age. Our matching nasal and blood data showed a strong interferon response in the airways with the induction of systemic interferon-stimulated populations, which were massively reduced in paediatric patients. Together, we provide several mechanisms that explain the milder clinical syndrome observed in children

Management of indwelling tunneled pleural catheters: a modified Delphi consensus statement

Background: The management of recurrent pleural effusions remains a challenging issue for clinicians. Advances in management have led to increased use of indwelling tunneled pleural catheters (IPC) because of their effectiveness and ease of outpatient placement. However, with the increase in IPC placement there have also been increasing reports of complications, including infections. Currently there is minimal guidance in IPC-related management issues after placement. Research Question: Our objective was to formulate clinical consensus statements related to perioperative and long-term IPC catheter management based on a modified Delphi process from experts in pleural disease management. Study Design and Methods: Expert panel members used a modified Delphi process to reach consensus on common perioperative and long-term management options related to IPC use. Members were identified from multiple countries, specialties, and practice settings. A series of meetings and anonymous online surveys were completed. Responses were used to formulate consensus statements among panel experts, using a modified Delphi process. Consensus was defined a priori as greater than 80% agreement among panel constituents. Results: A total of 25 physicians participated in this project. The following topics were addressed during the process: definition of an IPC infection, management of IPC-related infectious complications, interventions to prevent IPC infections, IPC-related obstruction/malfunction management, assessment of IPC removal, and instructions regarding IPC management by patients and caregivers. Strong consensus was obtained on 36 statements. No consensus was obtained on 29 statements. Interpretation: The management of recurrent pleural disease with IPC remains complex and challenging. This statement offers statements for care in numerous areas related to IPC management based on expert consensus and identifies areas that lack consensus. Further studies related to long-term management of IPC are warranted.</p