Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. 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, 2. The full clinical spectrum of COVID ranges from mild, self-limiting respiratory tract illness to severe progressive pneumonia, acute severe respiratory distress syndrome, multi-organ failure and death 1. Rapid investigations in basic virology made it possible to obtain the complete sequence of the RNA viral genome and thus to develop specific and sensitive molecular tests for a reliable detection of this new emerging virus in human respiratory samples 2.
Using some of referenced assays the SARS-CoV-2 RNA loads can be quantitatively estimated by threshold cycle Ct which values lower than 30 may be associated to infectious virus detectable by cell culture assays in the respiratory tract of symptomatic or asymptomatic carriers 4 , 5. To date, 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.
In the present study, we assessed the distribution of viral loads estimated by Ct values according to the presence of reported symptoms and to the delay between the respiratory sample and the onset of symptoms in study outpatients covering a large age-range. Following to the first national COVID lockdown occurring from 11 March to 13 May of , France initiated a massive viral screening strategy authorizing any person with or without a medical prescription to perform an RT-qPCR detection test for SARS-CoV-2, resulting in the performance of —, tests per week on an outpatient basis French national public health data.
For each study patient basic demographic data and reports of COVID symptoms and the time delay between the sampling and the onset of reported symptoms were recovered and registered by a medical pathologist MD at the time of the trans-nasal sample.
