Abstract
Objective: To validate and implement an optimized screening method for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA combining use of self-collected raw saliva samples, single-step heat-treated virus inactivation and RNA extraction, and direct RT-qPCR.
Methods: This was a three-phase study conducted in Barcelona (Spain) during June to October, 2020. The three phases were (1) analytical validation against standard RT-qPCR in saliva samples; (2) diagnostic validation against standard RT-qPCR using paired saliva-nasopharyngeal samples obtained from asymptomatic teenagers and adults in a sports academy; and (3) pilot screening of asymptomatic health workers in a tertiary hospital.
Results: In phase 1, the detection yield of the new method was comparable to that of standard RT-qPCR. In phase 2, the diagnostic sensitivity and specificity values in 303 self-collected saliva samples were 95.7% (95% confidence interval 79.0-99.2%) and 100.0% (95% confidence interval 98.6-100.0%), respectively. In phase 3, only 17 (0.6%) of the saliva samples self-collected by 2709 participants without supervision were invalid. The rapid analytical workflow with the new method (up to 384 batched samples could be processed in less than 2 hours) yielded 24 (0.9%) positive results in the remaining 2692 saliva samples. Paired nasopharyngeal specimens were all positive by standard RT-qPCR.
Conclusions: Direct RT-qPCR on self-collected raw saliva is a simple, rapid, and accurate method with potential to be scaled up for enhanced SARS-CoV-2 community-wide screening.
Keywords: COVID-19; PCR; SARS-CoV-2; Saliva; Screening; Surveillance.
【저자키워드】 COVID-19, SARS-CoV-2, Saliva, Screening, PCR, Surveillance, 【초록키워드】 Saliva, coronavirus, Phase 2, hospital, diagnostic, severe acute respiratory syndrome Coronavirus, RNA, RNA extraction, virus inactivation, RT-qPCR, Asymptomatic, Sensitivity and specificity, diagnostic sensitivity, Spain, Phase 3, health worker, Barcelona, Phase 1, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, 95% confidence interval, positive result, participant, supervision, saliva samples, positive, nasopharyngeal specimen, screening method, Direct, pilot screening, conducted, less, comparable, processed, scaled up, 【제목키워드】 SARS-COV-2 infection, validation, implementation, Non-invasive,