Evaluation of RT-qPCR of mouthwash and buccal swabs for detection of SARS-CoV-2 in children and adults.

Abstract Background The use of nasopharyngeal (NP) swabs as a specimen collection method to diagnose SARS-CoV-2 infection is frequently perceived as uncomfortable by patients and requires trained personnel. In this study, detection rate of SARS-CoV-2 in mouthwash samples and buccal swabs were compared in both children and adults. Material and methods In patients admitted to hospital with confirmed COVID-19 within the previous 72 hours, NP and buccal swabs as well as mouthwash samples were collected. RT-qPCR was performed on all samples. Results In total, 170 samples were collected from 155 patients (137 adults and 18 children). Approximately 91.7% of the collected NP swabs were positive in RT-PCR compared to 63.1% of mouthwash samples and 42.4% of buccal swabs. Compared to NP swabs, the sensitivity of using mouthwash was 96.3% and 65.4% for buccal swabs in NP swab samples with a CT value Discussion Mouthwash presents an alternative collection method for detecting SARS-CoV-2 in the case of unfeasible NP swab sampling. Buccal swabs should not be used due to their low sensitivity.