Comparison of SARS-CoV-2 detection in nasopharyngeal swab and saliva

We prospectively compared the efficacy of PCR detection of SARS-CoV-2 between paired nasopharyngeal and saliva samples in 76 patients including ten COVID-19 patients. The overall concordance rate of the virus detection between the two samples was 97.4% (95%CI, 90.8-99.7). Viral load was equivalent in COVID-19 patients, but the virus tended to disappear earlier in saliva at convalescent phase compared to nasopharyngeal 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.