The early identification of asymptomatic yet infectious cases is vital to curb the 2019 coronavirus (COVID-19) pandemic and to control the disease in the post-pandemic era. In this paper, we propose a fast, inexpensive and high-throughput approach using painless nasal-swab self-collection followed by direct RT-qPCR for the sensitive PCR detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This approach was validated in a large prospective cohort study of 1038 subjects, analysed simultaneously using (1) nasopharyngeal swabs obtained with the assistance of healthcare personnel and analysed by classic two-step RT-qPCR on RNA isolates and (2) nasal swabs obtained by self-collection and analysed with direct RT-qPCR. Of these subjects, 28.6% tested positive for SARS-CoV-2 using nasopharyngeal swab sampling. Our direct RT-qPCR approach for self-collected nasal swabs performed well with results similar to those of the two-step RT-qPCR on RNA isolates, achieving 0.99 positive and 0.98 negative predictive values (cycle threshold [Ct] < 37). Our research also reports on grey-zone viraemia, including samples with near-cut-off Ct values (Ct ≥ 37). In all investigated subjects (n = 20) with grey-zone viraemia, the ultra-small viral load disappeared within hours or days with no symptoms. Overall, this study underscores the importance of painless nasal-swab self-collection and direct RT-qPCR for mass testing during the SARS-CoV-2 pandemic and in the post-pandemic era.
【저자키워드】 COVID-19, self-collection, PCR diagnostics, Mass molecular testing, Nasal mid-turbinate swab, Post-pandemic era, 【초록키워드】 SARS-CoV-2, coronavirus, pandemic, SARS-CoV-2 pandemic, prospective cohort study, severe acute respiratory syndrome Coronavirus, RNA, Nasopharyngeal swab, RT-qPCR, Viral, PCR, Asymptomatic, Viral load, cycle threshold, nasopharyngeal swabs, Research, predictive values, nasal swab, respiratory, healthcare personnel, isolates, Negative predictive value, Ct values, followed by, classic, no symptoms, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, subject, assistance, Viraemia, positive, nasal swabs, isolate, approach, tested, performed, investigated, the disease, analysed, subjects, the SARS-CoV-2, 【제목키워드】 RT-qPCR, the SARS-CoV-2,