Comparable performance of antigen-detecting rapid test by healthcare worker-collected and self-collected swabs for SARS-CoV-2 diagnostic: A systematic review and meta-analysis.

Usage of self-screening tests has become increasingly relevant in public health perspective for early detection of SARS-CoV-2 infection in the transitioning era of the COVID-19 pandemic into an endemic. This study was designed to compare the diagnostic accuracy of self-conducted and health professional-conducted SARS-CoV-2 rapid antigen tests (Ag-RDTs) and whether the sample was taken from anterior nasal or nasal mid-turbinate. Eligible comparative Ag-RDTs accuracy studies were retrieved from electronic databases systematically, in accordance with PRISMA. Selected studies were assessed for risk of bias using QUADAS-2 and QUADAS-C. In total, we selected five out of 1952 studies retrieved using the keywords. The overall sensitivity for the self-collected nasal swab method and healthcare worker-collected nasopharyngeal swab method was 79% (95% CI 68-87; I2  = 62%) and 83% (95% CI 75-89; I2  = 32%), respectively, which was not statistically different (p = 0.499). Nasal mid-turbinate swabs have a significantly higher sensitivity compared to anterior nasal swabs (p < 0.01). Both sampling methods represent high and comparable specificity values of 98% (95% CI 97-99; I2  = 0%) and 99% (95% CI 98-99; I2  = 0%). Positive predictive value (range 90%-99%) and negative predictive value (range 87%-98%) were equivalent for both methods. Our findings indicated the accuracy of self-collected Ag-RDT on nasal swabs was comparable to those performed by healthcare worker-collected on nasopharyngeal swabs. Self-collected Ag-RDT could be considered as a transmission prevention method in the transition of COVID-19 pandemic.

Human Dendritic Cells with Th2-Polarizing Capacity: Analysis Using Label-Free Quantitative Proteomics.

BACKGROUND: Dendritic cells (DCs) are the sentinels of the immune system. Upon recognition of a pathogen, they mature and migrate to draining lymph nodes to prime and polarize T cell responses. Although it is known that helminths and helminth-derived molecules condition DCs to polarize T helper (Th) cells towards Th2, the underlying mechanisms remain incompletely understood. OBJECTIVES: The aim of this study was to conduct a proteome analysis of helminth antigen-stimulated DCs in order to gain more insight into the cellular processes associated with their ability to polarize immune responses. METHODS: We analyzed the maturation and polarization of monocyte-derived DCs from 9 donors at 2 different time points after stimulation with different Th1- and Th2-polarizing pathogen-derived molecules. The samples were measured using liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry for relative quantitation. RESULTS: Lipopolysaccharide-induced maturation promoted the expression of proteins related to metabolic, cellular, and immune system processes. Th1-polarizing DCs, conditioned by IFN-γ during maturation, displayed accelerated maturation by differentially expressing cytoskeletal proteins and proteins involved in immune regulation. The stimulation of DCs with soluble egg antigens and omega-1 derived from Schistosoma mansoni, which are both Th2-inducing stimuli, increased 60S acidic ribosomal protein P2, and vesicle amine transferase 1 while decreasing the expression of proteins related to antigen processing and presentation. CONCLUSION: Our data indicate that not only proteins involved in the interaction between T cells and DCs at the level of the immunological synapse, but also those related to cellular metabolism and stress, may promote Th2 polarization.

Accelerating the Laboratory Testing Capacity through Saliva Pooling Prior to Direct RT-qPCR for SARS-CoV-2 Detection.

The testing capacity of the laboratory is paramount for better control of the pandemic caused by SARS-CoV-2. The pooling method is promising to increase testing capacity, and the use of direct NAAT-based detection of SARS-CoV-2 on a non-invasive specimen such as saliva will ultimately accelerate the testing capacity. This study aims to validate the pooling-of-four method to quadruple the testing capacity using RNA-extraction-free saliva specimens. In addition, we intend to investigate the preferable stage of pooling, including pre- or post-heating. The compatibility of this approach was also tested on five commercial kits. Saliva specimens stored at -80 °C for several months were proven viable and were used for various tests in this study. Our findings revealed that pooling-of-four specimens had an overall agreement rate of 98.18% with their individual testing. Moreover, we proved that the pooling procedure could be conducted either pre- or post-heating, with no discordance and no significant difference in Ct values generated. When compared to other commercial detection kits, it demonstrated an overall agreement greater than 85%, which exhibits broad compatibility and ensures easy adaptability in clinical settings. This method has been proven reliable and increases the testing capacity up to fourfold.

Wide Application of Minimally Processed Saliva on Multiple RT-qPCR Kits for SARS-CoV-2 Detection in Indonesia.

Saliva as a sample matrix has been an attractive alternative for the detection of SARS-CoV-2. However, due to potential variability in collection and processing steps, evaluating a proposed workflow amongst the local population is recommended. Here, we aim to validate the collection and treatment of human saliva as a direct specimen for RT-qPCR-based detection of SARS-CoV-2 in Indonesia. We demonstrated that SARS-CoV-2 target genes were detected in saliva specimens and remained stable for five days either refrigerated or stored at room temperature. The method of processing saliva specimens described in this report bypasses the need for an RNA-extraction process, thereby reducing the cost, time, and manpower required for processing samples. The developed method was tested across nine commercial kits, including the benchmark, to demonstrate its wide applicability on multiple existing workflows. Our developed method achieved an 86% overall agreement rate compared to paired nasopharyngeal and oropharyngeal swab specimens (NPOP). With the assistance of a saliva sampling device, the collection was found to be more convenient for individuals and improved the overall agreement rate to 97%.