SARS-CoV-2 detection in setting of viral swabs scarcity: Are MRSA swabs and viral swabs equivalent?

Pre-analytical sample stabilization by different sampling devices for PCR-based COVID-19 diagnostics

The outbreak of the SARS-CoV-2 pandemic created an unprecedented requirement for diagnostic testing, challenging not only healthcare workers and laboratories, but also providers. Quantitative RT-PCR of various specimen types is considered the diagnostic gold standard for the detection of SARS-CoV-2, both in terms of sensitivity and specificity. The pre-analytical handling of patient specimens is a critical factor to ensure reliable and valid test results. Therefore, the effect of storage duration and temperature on SARS-CoV-2 RNA copy number stability was examined in various commercially available specimen collection, transport and storage devices for naso/oropharyngeal swabs and saliva. The swab specimen transport and storage devices tested showed no significant alteration of viral RNA copy numbers when stored at room temperature, except for one system when stored for up to 96 h. However, at 37 °C a significant reduction of detectable RNA was found in 3 out of 4 of the swab solutions tested. It was also found that detectability of viral RNA remained unchanged in all 7 saliva devices as well as in unstabilized saliva when stored for 96 h at room temperature, but one device showed marked RNA copy number loss at 37 °C. All tested saliva collection devices inhibited SARS-CoV-2 infectivity immediately, whereas SARS-CoV-2 remained infectious in the swab transport systems examined, which are designed to be used for viral or bacterial growth in cell culture systems.

Uncoupling Molecular Testing for SARS-CoV-2 From International Supply Chains

The rapid global rise of COVID-19 from late 2019 caught major manufacturers of RT-qPCR reagents by surprise and threw into sharp focus the heavy reliance of molecular diagnostic providers on a handful of reagent suppliers. In addition, lockdown and transport bans, necessarily imposed to contain disease spread, put pressure on global supply lines with freight volumes severely restricted. These issues were acutely felt in New Zealand, an island nation located at the end of most supply lines. This led New Zealand scientists to pose the hypothetical question: in a doomsday scenario where access to COVID-19 RT-qPCR reagents became unavailable, would New Zealand possess the expertise and infrastructure to make its own reagents onshore? In this work we describe a review of New Zealand's COVID-19 test requirements, bring together local experts and resources to make all reagents for the RT-qPCR process, and create a COVID-19 diagnostic assay referred to as HomeBrew (HB) RT-qPCR from onshore synthesized components. This one-step RT-qPCR assay was evaluated using clinical samples and shown to be comparable to a commercial COVID-19 assay. Through this work we show New Zealand has both the expertise and, with sufficient lead time and forward planning, infrastructure capacity to meet reagent supply challenges if they were ever to emerge.

On-Site, On-Demand 3D-Printed Nasopharyngeal Swabs to Improve the Access of Coronavirus Disease-19 Testing

Diagnostic testing that facilitates containment, surveillance, and treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or future respiratory viruses, depends on a sample collection device that efficiently collects nasopharyngeal tissue and that can be manufactured on site when an outbreak or public health emergency is declared by a government. Here two novel stereolithography-based three-dimensional (3D)-printed nasopharyngeal swabs are reported which are made using a biocompatible and sterilizable photoresist. Such swabs are readily manufactured on-site and on-demand to ensure availability, if supply chain shortages emerge. Additionally, the 3D-printed swabs easily adapt to current workflow and testing procedures in hospital clinical laboratories to allow for effortless scaling up of test kits. Finally, the 3D-printed nasopharyngeal swabs demonstrate concordant SARS-CoV-2 testing results between the 3D-printed swabs and the COPAN commercial swabs, and enable detection of SARS-CoV-2 in clinical samples obtained from autopsies.

Limit of detection in different matrices of 19 commercially available rapid antigen tests for the detection of SARS-CoV-2

In the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days' storage at - 80 °C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 102 pfu/ml (1.0 × 106 genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of 19 Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at - 80 °C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.

Relative sensitivity of anterior nares and nasopharyngeal swabs for initial detection of SARS-CoV-2 in ambulatory patients: Rapid review and meta-analysis

Nasopharyngeal (NP) swabs are considered "gold standard" for diagnosing SARS-CoV-2 infections, but anterior nares or mid-turbinate swabs (nasal swabs) are often used. We performed a meta-analysis comparing the sensitivity of nasal and nasopharyngeal swabs against a composite reference standard for the initial diagnosis of SARS-CoV-2 infection in ambulatory patients. The study is registered on PROSPERO (CRD42020221827). Data sources included studies appearing between January 1, 2020 and March 20, 2021, identified by searches of PubMed, medRxiv and bioRxiv. Studies included at least 20 subjects who simultaneously provided nasal and nasopharyngeal specimens for reverse transcription-polymerase chain reaction testing, and for which confusion matrices could be constructed. Authors individually assessed studies for inclusion and compared assessments. Each author independently extracted all data elements; differences were reconciled by review of initial data sources. Extracted data included specimen site, patient characteristics, collection site, and confusion matrices comparing results for nasal and nasopharyngeal swabs. Assessed against a composite reference standard, anterior nares swabs are less sensitive (82% - 88%) than nasopharyngeal swabs (98%). For populations with 10% specimen positivity, the negative predictive values of all swab types were greater than 98%. Mid-turbinate and anterior nares swabs seem to perform similarly. The lower sensitivity associated with nasal swab SARS-CoV-2 diagnosis is justified by the ability to screen more patients and reduced personal protective equipment requirements. Our conclusions are limited by the small number of studies and the significant heterogeneity of study designs and study outcomes.

SARS-CoV-2 Genome from the Khyber Pakhtunkhwa Province of Pakistan

Among viral outbreaks, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the deadliest ones, and it has triggered the global COVID-19 pandemic. In Pakistan, until 5th September 2020, a total of 6342 deaths have been reported, of which 1255 were from the Khyber Pakhtunkhwa (KPK) province. To understand the disease progression and control and also to produce vaccines and therapeutic efforts, whole genome sequence analysis is important. In the current investigation, we sequenced a single sample of SARS-CoV-2 genomes (accession no. MT879619) from a male suspect from Peshawar, the KPK capital city, during the first wave of infection. The local SARS-CoV-2 strain shows some unique characteristics compared to neighboring Iranian and Chinese isolates in phylogenetic tree and mutations. The circulating strains of SARS-CoV-2 represent an intermediate evolution from China and Iran. Furthermore, eight complete whole genome sequences, including the current Pakistani isolates which have been submitted to Global Initiative on Sharing All Influenza Data (GSAID), were also investigated for specific mutations and characters. Some novel mutations [NSP2 (D268del), NSP5 (N228K), and NS3 (F105S)] and specific characters have been detected in the coding regions, which may affect viral transmission, epidemiology, and disease severity. The computational modeling revealed that a majority of these mutations may have a stabilizing effect on the viral protein structure. In conclusion, the genome sequencing of local strains is important for better understanding the pathogenicity, immunogenicity, and epidemiology of causative agents.