Asymptomatic COVID-19 Adult Outpatients identified as Significant Viable SARS-CoV-2 Shedders

Marie Glenet,Yohan N’Guyen,Ittah Meyer,Anne-Laure Lebreil,Laurent Andreoletti,Laetitia Heng

doi:10.1038/s41598-021-00142-8

Marie Glenet, Yohan N’Guyen + Show 4 more

Open Access

https://doi.org/10.1038/s41598-021-00142-8

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Abstract

Differential kinetics of RNA loads and infectious viral levels in the upper respiratory tract between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations that may guide clinical management, infection control measures and occupational health decisions. In the present investigation, 496 (2.8%) of 17,911 French adult outpatients were positive for an upper respiratory tract SARS-CoV-2 RNA detection by a quantitative RT-PCR assay, of which 180 (36.3%) were COVID-19 asymptomatic. Of these adult asymptomatic viral shedders, 75% had mean to high RNA viral loads (Ct values < 30) which median value was significantly higher than that observed in symptomatic subjects (P = 0.029), and 50.6% were positive by cell culture assays of their upper respiratory tract specimens. Our findings indicate that COVID-19 asymptomatic adult outpatients are significant viable SARS-CoV-2 shedders in their upper respiratory tract playing a major potential role as SARS-CoV-2 transmitters in various epidemiological transmission chains, promoting COVID-19 resurgence in populations.

Highlights

Differential kinetics of RNA loads and infectious viral levels in the upper respiratory tract between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations that may guide clinical management, infection control measures and occupational health decisions
We identified two distinct subsets of viral load values that were strongly segregated by a cut-off cycle threshold (Ct) value of 30 in both asymptomatic and symptomatic patients (P < 10–4) and this result appeared to be not associated with significant differences in median age levels between these two subgroups (P = 0.85) (Fig. 1B)
We found that the proportion of asymptomatic patients with low viral loads was significantly higher than that observed in symptomatic patients (Ct values ≥ 30: 25% versus 11.7%, P = 0.003, Fig. 1B)

Summary

Introduction

Differential kinetics of RNA loads and infectious viral levels in the upper respiratory tract between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations that may guide clinical management, infection control measures and occupational health decisions. 496 (2.8%) of 17,911 French adult outpatients were positive for an upper respiratory tract SARS-CoV-2 RNA detection by a quantitative RT-PCR assay, of which 180 (36.3%) were COVID-19 asymptomatic. Differential kinetics of RNA loads and infectious viral levels between asymptomatic and symptomatic SARS-CoV-2 infected adult outpatients remain unclear limiting recommendations about the use of respiratory tract Ct values that may guide clinical management, infection control measures and occupational health decisions[3,4]. Among identified COVID-19 asymptomatic patients with high viral RNA loads, we investigated the presence of infectious SARSCoV-2 particles in their upper respiratory tract specimens by cell culture assays

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