Detection of SARS-CoV-2 using qRT-PCR in saliva obtained from asymptomatic or mild COVID-19 patients, comparative analysis with matched nasopharyngeal samples

• Published in: PloS one 2021-01, Vol.16 (6), p.e0252964
• Main Authors: Kenji Ota, Katsunori Yanagihara, Daisuke Sasaki, Norihito Kaku, Naoki Uno, Kei Sakamoto, Kosuke Kosai, Taiga Miyazaki, Hiroo Hasegawa, Ayumi Fujita, Masato Tashiro, Takeshi Tanaka, Koichi Izumikawa, Koya Ariyoshi, Hiroshi Mukae, Jiro Yasuda, Kouichi Morita, Shigeru Kohno
• Format: Article
• Language: English
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0252964

ObjectivesThe accurate detection of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is essential for the diagnosis of coronavirus disease 2019 (COVID-19). We compared the quantitative RT-PCR results between nasopharyngeal swabs and saliva specimens.MethodsA COVID-19 outbreak occurred on a cruise ship at Nagasaki port, Japan. We obtained 123 nasopharyngeal swabs and saliva each from asymptomatic or mild patients in the late phase of infection.ResultsThe intervals from the diagnosis to the sampling were 25.5 days for nasopharyngeal swabs and 28.9 days for saliva. The positive rate was 19.5% (24/123) for nasopharyngeal swabs and 38.2% (47/123) for saliva (P = 0.48). The quantified viral copies (mean ± SEM copies/5 μl) were 9.3±2.6 in nasopharyngeal swabs and 920±850 in saliva (P = 0.0006).ConclusionsThe advantages of saliva specimens include positive rate improvement and accurate viral load detection. Saliva may be used as a reliable sample for SARS-CoV-2 detection.