Molecular Detection of SARS-CoV-2 Viral Particles in Exhaled Breath Condensate via Engineered Face Masks

In this study, we present a novel face mask engineered for the collection of exhaled breath condensate (EBC) and its application and performance in a clinical study of COVID-19 infection status assessment versus the gold standard polymerase chain reaction (PCR) nasopharyngeal swab testing. EBC was collected within a clinical trial of COVID-19-infected and non-infected patients and analyzed by reverse transcription quantitative (RT-q) PCR, with the results being compared with nasopharyngeal sampling of the same patient. The cycle threshold (Ct) values of the nasopharyngeal samples were generally lower than those of EBC, with viral loads in EBC ranging from 1.2 × 104 to 5 × 108 viral particles mL−1 with 5 min of breathing. From the 60 clinical patients’ samples collected, 30 showed a confirmed SARS-CoV-2 infection. Of these 30 individuals, 22 (73%) had Ct values < 40 (representing the threshold for SARS-CoV-2 infectivity) using both amplification of ORF1a/b and the E-gene. The 30 EBC samples from non-infected participants were all identified as negative, indicating a 100% specificity. These first results encourage the use of the face mask as a noninvasive sampling method for patients with lung-related diseases, especially with a view to equipping the face mask with miniaturized sensing devices, representing a true point-of-care solution in the future.