SARS-CoV-2 RNA in exhaled air of hospitalized COVID-19 patients

Abstract

Knowledge about contagiousness is key to accurate management of hospitalized COVID-19 patients. Epidemiological studies suggest that in addition to transmission through droplets, aerogenic SARS-CoV-2 transmission contributes to the spread of infection. However, the presence of virus in exhaled air has not yet been sufficiently demonstrated. In pandemic situations low tech disposable and user-friendly bedside devices are required, while commercially available samplers are unsuitable for application in patients with respiratory distress. We included 49 hospitalized COVID-19 patients and used a disposable modular breath sampler to measure SARS-CoV-2 RNA load in exhaled air samples and compared these to SARS-CoV-2 RNA load of combined nasopharyngeal throat swabs and saliva. Exhaled air sampling using the modular breath sampler has proven feasible in a clinical COVID-19 setting and demonstrated viral detection in 25% of the patients.

Figure 1

(a) Modular breath sampler. During sampling, the patient breathes through the mouthpiece; inhaling (I) and exhaling (II). The exhaled air is guided through the sampler to the diffuser into the capture buffer. The exhaled air leaves the sampler on the back end. After sampling, the collection tube can be disconnected and stored for analysis. (b) Correlation plot depicting SARS-CoV-2 viral RNA load measured in nasopharyngeal throat swab and saliva samples. (c) SARS-CoV-2 RNA detection in exhaled air samples and nasopharyngeal throat swab samples. Filled dots () represent cases in which SARS-CoV-2 RNA was detected in exhaled air samples. Open dots (○) represent cases in which SARS-CoV-2 RNA was not detected.