Detection of SARS-CoV-2 in Exhaled Breath from Non-Hospitalized COVID-19-Infected Individuals: A Proof-of-Concept Study

Background: The diagnosis of COVID-19 is based on detection of SARS-CoV-2 in oro-/nasopharyngel swabs, but because of uncomfortness and minor risk for the tested individual during the swab procedure, detection of SARS-CoV-2 has been investigated in other biological matrixes.Methods: In this proof-of-concept study, confirmed SARS-CoV-2-infected individuals performed a daily air sample through five days. Air samples were obtained through a non-invasive electrostatic air sampler. Detection of SARS-CoV-2 RNA were determined with qRT-PCR. The association of positive samples with clinical characteristics was evaluated through mixed-effect models.Results: We obtained 665 air samples from 111 included patients with confirmed SARS-CoV-2 infection. Overall, 52 individuals (46.8%) had at least one positive air sample, and 129 (19.4%) air samples were positive for SARS-CoV-2. Patients with symptoms or a symptom duration ≤ four days had significantly higher odds of having a positive air sample. Cycle threshold values were significantly lower in samples obtained ≤ 4 days from symptom onset. Neither variant of SARS-CoV-2 nor method of air sampling were associated with a positive air sample.Conclusion: We demonstrate that SARS-CoV-2 is detectable in human breath, and suggest further evaluation of air sampling considering the non-invasive, point-of-care method.