Excellent option for mass testing during the SARS-CoV-2 pandemic: painless self-collection and direct RT-qPCR

Abstract

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.

COVID-19 with high-sensitivity CRP associated with worse dynamic clinical parameters and outcomes

“…Interestingly, patients with high hsCRP levels had shorter survival rates, especially those with a high viral load. The present study suggests the association between patients with either high hsCRP or SAR-CoV-2 viral loads and high mortality due to high viral burden and high inflammation conditions (15)(16)(17)(18) This study adds to this evidence by demonstrating that hsCRP levels at admission possess similar discriminatory ability, suggesting its potential utility as a readily available and cost-effective marker. Most studies that used CRP demonstrated that this test is related to increased mortality rates due to the viral destruction of the vascular injury process.…”

Evaluation of the Practicability of Biosynex Antigen Self-Test COVID-19 AG+ for the Detection of SARS-CoV-2 Nucleocapsid Protein from Self-Collected Nasal Mid-Turbinate Secretions in the General Public in France

“…Previous studies to date have looked at the performance of unobserved as well as supervised self-collected specimens for molecular detection of SARS-CoV-2 [ 45 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ]. Thus, Tu and colleagues compared SARS-CoV-2 detection using a variety of swab types self-collected (under health care professional observation) by 530 symptomatic child and adult outpatients (or their parents or guardians), with nasopharyngeal swabs collected by health care professionals as the comparator gold standard [ 72 ].…”

Distribution of SARS-CoV-2 Lineages in the Czech Republic, Analysis of Data from the First Year of the Pandemic

“…The present study has several limitations in terms of interpretation of evidence of superinfection we found in ~10% of analysed samples. Due to the specific features of SARS-CoV-2 RT-qPCR diagnostics [ 28 ] related to extremely high diversity of viral copies in individual samples and a vast number of analysed samples in diagnostic laboratories, contamination of samples cannot be completely excluded. On the other hand, all samples came from accredited and experienced diagnostic laboratories with established laboratory quality control systems (often ISO15189:2013; data available upon request), which ought to minimise the likelihood of accidental contamination.…”