SARS-CoV-2 shedding dynamics across the respiratory tract, sex, and disease severity for adult and pediatric COVID-19

Abstract

Background:Previously, we conducted a systematic review and analyzed the respiratory kinetics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Chen et al., 2021). How age, sex, and coronavirus disease 2019 (COVID-19) severity interplay to influence the shedding dynamics of SARS-CoV-2, however, remains poorly understood.Methods:We updated our systematic dataset, collected individual case characteristics, and conducted stratified analyses of SARS-CoV-2 shedding dynamics in the upper (URT) and lower respiratory tract (LRT) across COVID-19 severity, sex, and age groups (aged 0–17 years, 18–59 years, and 60 years or older).Results:The systematic dataset included 1266 adults and 136 children with COVID-19. Our analyses indicated that high, persistent LRT shedding of SARS-CoV-2 characterized severe COVID-19 in adults. Severe cases tended to show slightly higher URT shedding post-symptom onset, but similar rates of viral clearance, when compared to nonsevere infections. After stratifying for disease severity, sex and age (including child vs. adult) were not predictive of respiratory shedding. The estimated accuracy for using LRT shedding as a prognostic indicator for COVID-19 severity was up to 81%, whereas it was up to 65% for URT shedding.Conclusions:Virological factors, especially in the LRT, facilitate the pathogenesis of severe COVID-19. Disease severity, rather than sex or age, predicts SARS-CoV-2 kinetics. LRT viral load may prognosticate COVID-19 severity in patients before the timing of deterioration and should do so more accurately than URT viral load.Funding:Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant, NSERC Senior Industrial Research Chair, and the Toronto COVID-19 Action Fund.

Effect of monoclonal antibody therapy on the endogenous SARS-CoV-2 antibody response

“…Since only Ct values were available for the upper respiratory tract, we cannot rule out the possibility of greater differences in viral loads in other locations. Viral loads persist longer in the lower respiratory tract of those with more severe disease as would be the case among untreated subjects [ 32 ].…”

Case Report: Severe Acute Pulmonary COVID-19 in a Teenager Post Autologous Hematopoietic Stem Cell Transplant

“…We observed minor discrepancies between SARS-CoV-2 Ct values in nose–throat swab samples and bronchoalveolar lavage samples. Different sample sites and volumes can explain this, and it has been observed in immunocompetent patients that viral loads peak on average 2 weeks after symptom onset in lower-respiratory-tract samples, whereas viral loads decrease on average 1 week after symptom onset in the upper respiratory tract ( 19 , 20 ). When available, clinical decisions were based on sample positivity, using Ct values as a guide of viral activity, as we suspected clearing SARS-CoV-2 from the lungs would take longer due to prolonged immunosuppression and clinical condition.…”

A Potential Role of the CD47/SIRPalpha Axis in COVID-19 Pathogenesis

“…High SARS-CoV-2 loads are associated with more severe COVID-19 and a higher risk of patient death [77,78]. Therefore, high CD47 and/or SIRPα levels may affect initial virus control resulting in enhanced virus levels, which may eventually lead to the hyperinflammation and immunopathology observed in severe COVID-19.…”