Prognostic factors for mortality, ICU, MIS-C and hospital admission due to SARS-CoV-2 in paediatric patients: A systematic review and meta-analysis (preprint)

ABSTRACT Background: There is a paucity of data on the factors associated with severe COVID-19 disease, especially in children. This systematic review and meta-analysis aim to identify the risk factors for acute adverse outcomes of COVID-19 within paediatric populations, using the recruitment setting as a proxy of initial disease severity. Methods: A systematic review and meta-analysis were performed representing published evidence from the start of the pandemic up to 14 February 2022. Our primary outcome was the identification of risk factors for adverse outcomes, stratified by recruitment setting (community, hospital). No geographical restrictions were imposed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to evaluate the certainty in the body of evidence for each meta-analysis. In anticipation of significant clinical and methodological heterogeneity in the meta-analyses, we fitted logistic regression models with random effects. Findings: Our review identified 47 studies involving 94,210 paediatric cases of COVID-19. Infants up to 3 months were more likely to be hospitalised than older children. Gender and ethnicity were not associated with an increased likelihood of adverse outcomes among children within the community setting. Concerning comorbidities, having at least one pre-existing disease increased the odds of hospitalisation. Concerning BMI, underweight children and severely obese were noted to have an increased likelihood of hospital admission. The presence of metabolic disorders and children with underlying cardiovascular diseases, respiratory disorders, neuromuscular disorders and neurologic conditions were also more likely to be hospitalised. Concerning underlying comorbidities, paediatric hospitalised patients with congenital/genetic disease, those obese, with malignancy, cardiovascular diseases and respiratory disease were associated with higher odds of being admitted to ICU or ventilated. Interpretation: Our findings suggest that age, male, gender, and paediatric comorbidities increased the likelihood of hospital and ICU admission. Obesity, malignancy, and respiratory and cardiovascular disorders were among the most important risk factors for hospital and ICU admission among children with COVID-19. The extent to which these factors were linked to actual severity or where the application of cautious preventive care is an area in which further research is needed.

The role of educational settings in the transmission chain of SARS-CoV-2 in 2020: a systematic review (preprint)

BackgroundSchool closures have been used as a core Non pharmaceutical intervention during the COVID-19 pandemic, however the role of educational settings in COVID-19 transmission is still unclear. MethodsThis systematic literature review assessed studies published between December 2019 and April 1, 2021 in Medline and Embase, which included studies that assessed educational settings from approximately January 2020 to January 2021. The inclusion criteria were based on the PCC framework (P-Population, C-Concept, C-Context). The study Population was restricted to people 1-17 years old (excluding neonatal transmission), the Concept was to assess child-to-child and child-to-adult transmission, while the Context was to assess specifically educational setting transmission clusters. ResultsFifteen studies met inclusion criteria, ranging from daycare centers to high schools and summer camps, while eight studies assessed the re-opening of schools in the 2020-2021 school year. In principle although there is sufficient evidence that children can both be infected by and transmit SARS-CoV-2 in school settings, the SAR remain relatively low -when NPI measures are implemented in parallel. Moreover, although the evidence was limited there was an indication that younger children may have a lower SAR than adolescents. ConclusionsTransmission in educational settings in 2020 was minimal -when NPI measures were implemented in parallel. However, with an upsurge of cases related to variants of concern, continuous surveillance and assessment of the evidence is warranted to ensure the maximum protection of the health of students and the educational workforce, while also minimising the numerous negative impacts that school closures may have on children. Strengths and limitations of this studyO_LIThis study provides a rapid review of the peer-reviewed literature pertaining to SARS-CoV-2 transmission by children within educational settings. C_LIO_LIThe review reflects the status quo of the previous school years (January 2020 -January 2021) due to the lag time between study implementation, peer review and publication. C_LIO_LIThe included studies represent child-to-child transmission within the context of previous SARS-CoV-2 strains and are not directly applicable to newer variants. C_LI

Recovery of monocyte exhaustion is associated with resolution of lung injury in COVID-19 convalescence. (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection resulting in the clinical syndrome COVID-19 is associated with an exaggerated immune response and monocyte infiltrates in the lungs and other peripheral tissues. It is now increasingly recognised that chronic morbidity persists in some patients. We recently demonstrated profound alterations of monocytes in hospitalised COVID-19 patients. It is currently unclear whether these abnormalities resolve or progress following patient discharge. We show here that blood monocytes in convalescent patients at their 12 week follow up, have a greater propensity to produce pro-inflammatory cytokines TNF and IL-6, which was consistently higher in patients with resolution of lung injury as indicated by a normal chest X-ray and no shortness of breath (a key symptom of lung injury). Furthermore, monocytes from convalescent patients also displayed enhanced levels of molecules involved in leucocyte migration, including chemokine receptor CXCR6, adhesion molecule CD31/PECAM and integrins VLA-4 and LFA-1. Expression of migration molecules on monocytes was also consistently higher in convalescent patients with a normal chest X-ray. These data suggest persistent changes in innate immune function following recovery from COVID-19 and indicate that immune modulating therapies targeting monocytes and leucocyte migration may be useful in recovering COVID-19 patients with persistent symptoms.

SARS-CoV-2 S protein ACE2 interaction reveals novel allosteric targets (preprint)

The Spike (S) protein is the main handle for SARS-CoV-2 to enter host cells through surface ACE2 receptors. How ACE2 binding activates proteolysis of S protein is unknown. Here, we have mapped the S:ACE2 interface and uncovered long-range allosteric propagation of ACE2 binding to sites critical for viral host entry. Unexpectedly, ACE2 binding enhances dynamics at a distal S1/S2 cleavage site and flanking protease docking site ~27 [A] away while dampening dynamics of the stalk hinge (central helix and heptad repeat) regions ~ 130 [A] away. This highlights that the stalk and proteolysis sites of the S protein are dynamic hotspots in the pre-fusion state. Our findings provide a mechanistic basis for S:ACE2 complex formation, critical for proteolytic processing and viral-host membrane fusion and highlight protease docking sites flanking the S1/S2 cleavage site, fusion peptide and heptad repeat 1 (HR1) as allosterically exposed cryptic hotspots for potential therapeutic development.