ABSTRACT
We prospectively compared the efficacy of PCR detection of SARS-CoV-2 between paired nasopharyngeal and saliva samples in nine COVID-19 patients. SARS-CoV-2 was detected in saliva in 8 of 9 (89%) patients and in all 11 samples taken within 2 weeks after disease onset. Viral load was equivalent at earlier time points but declined in saliva than nasopharyngeal samples. PCR negativity was also concordant in all 27 saliva samples from 24 patients between nasopharyngeal and saliva samples. These results suggest that saliva is a reliable noninvasive alternative to nasopharyngeal swabs and facilitate widespread PCR testing in the face of shortages of swabs and protective equipment without posing a risk to healthcare workers.
ABSTRACT
Rapid detection of SARS-CoV-2 is critical for the diagnosis of coronavirus disease 2019 (COVID-19) and preventing the spread of the virus. A novel "2019 Novel Coronavirus Detection Kit (nCoV-DK)" halves detection time by eliminating the steps of RNA extraction and purification. We evaluated concordance between the nCoV-DK and direct PCR. The virus was detected in 53/71 fresh samples by the direct method and 55/71 corresponding frozen samples by the nCoV-DK. The overall concordance rate of the virus detection between the two methods was 94.4% (95% CI, 86.2-98.4). Concordance rates were 95.2% (95% CI, 83.8-99.4), 95.5% (95% CI, 77.2-99.9), 85.7% (95% CI, 42.1-99.6) in nasopharyngeal swab, saliva, and sputum samples, respectively. These results indicate that the nCoV-DK effectively detects SARS-CoV-2 in all types of the samples including saliva, while reducing time required for detection, labor, and risk of human error.
