Prospective Comparison of Saliva and Nasopharyngeal Swab Sampling for Mass Screening for COVID-19

Current testing for COVID-19 relies on reverse-transcriptase polymerase chain reaction from a nasopharyngeal swab specimen. Saliva samples have advantages regarding ease and painlessness of collection, which does not require trained staff may allow self-sampling. We enrolled 776 persons at various field-testing sites collected pooled saliva samples. One hundred sixty two had positive RT-PCR, 61% were mildly symptomatic 39% asymptomatic. The sensitivity RT-PCR vs. nasopharygeal swabs varied depending the patient groups considered or Ct thresholds. There 10 (6.2%) patients with sample negative swab, all whom values <25 three genes. For interval between symptoms onset sampling was <10 days 77% but when excluding isolated N gene positivity (54/162), 90%. In asymptomatic patients, only 24%. When we looked Cts <30, 83 88.9% considering relatively good performance low suggests that could be useful acceptable tool to identify infectious in mass screening contexts, strategically important task contact tracing isolation community.