Multicenter Diagnostic Evaluation of a Novel Coronavirus Antigen Lateral Flow Test among Symptomatic Individuals in Brazil and the United Kingdom.

The COVID-19 pandemic has led to the commercialization of many antigen-based rapid diagnostic tests (Ag-RDTs), requiring independent evaluations. This report describes the clinical evaluation of the Novel Coronavirus 2019-nCoV Antigen Test (Colloidal Gold) (Beijing Hotgen Biotech Co., Ltd.), at two sites within Brazil and one in the United Kingdom. The collected samples (446 nasal swabs from Brazil and 246 nasopharyngeal samples from the UK) were analyzed by the Ag-RDT and compared to reverse transcription-quantitative PCR (RT-qPCR). Analytical evaluation of the Ag-RDT was performed using direct culture supernatants of SARS-CoV-2 strains from the wild-type (B.1), Alpha (B.1.1.7), Delta (B.1.617.2), Gamma (P.1), and Omicron (B.1.1.529) lineages. An overall sensitivity and specificity of 88.2% (95% confidence interval [CI], 81.3 to 93.3) and 100.0% (95% CI, 99.1 to 100.0), respectively, were obtained for the Brazilian and UK cohorts. The analytical limit of detection was determined as 1.0 × 103 PFU/mL (Alpha), 2.5 × 102 PFU/mL (Delta), 2.5 × 103 PFU/mL (Gamma), and 1.0 × 103 PFU/mL (Omicron), giving a viral copy equivalent of approximately 2.1 × 104 copies/mL, 9.0 × 105 copies/mL, 1.7 × 106 copies/mL, and 1.8 × 105 copies/mL for the Ag-RDT, respectively. Overall, while a higher sensitivity was claimed by the manufacturers than that found in this study, this evaluation finds that the Ag-RDT meets the WHO minimum performance requirements for sensitivity and specificity of COVID-19 Ag-RDTs. This study illustrates the comparative performance of the Hotgen Ag-RDT across two global settings and considers the different approaches in evaluation methods. IMPORTANCE Since the beginning of the SARS-CoV-2 pandemic, we have witnessed growing numbers of antigen rapid diagnostic tests (Ag-RDTs) being brought to market. In the United Kingdom, this was somewhat controlled indirectly as the government offered free tests from a small number of companies. However, as this has now ceased, individuals are responsible for their own acquisition of test kits. Similarly in Brazil, as of January 2022, pharmacies and other health care retailers are permitted to sell Ag-RDTs directly to the community. Many of these Ag-RDTs have not been externally evaluated, and results are not readily available to the public. Thus, there is now a need for a transparent evaluation of Ag-RDTs with both analytical and clinical evaluation. We present an independent review of the Novel Coronavirus 2019-nCoV Antigen Test (Colloidal Gold) (Beijing Hotgen Biotech Co., Ltd.), at two sites within Brazil and one in the United Kingdom.

Accuracy and ease-of-use of seven point-of-care SARS-CoV-2 antigen-detecting tests: A multi-centre clinical evaluation.

BACKGROUND: Antigen-detecting rapid diagnostic tests (Ag-RDTs) for SARS-CoV-2 are important diagnostic tools. We assessed clinical performance and ease-of-use of seven Ag-RDTs in a prospective, manufacturer-independent, multi-centre cross-sectional diagnostic accuracy study to inform global decision makers. METHODS: Unvaccinated participants suspected of a first SARS-CoV-2 infection were recruited at six sites (Germany, Brazil). Ag-RDTs were evaluated sequentially, with collection of paired swabs for routine reverse transcription polymerase chain reaction (RT-PCR) testing and Ag-RDT testing. Performance was compared to RT-PCR overall and in sub-group analyses (viral load, symptoms, symptoms duration). To understandusability a System Usability Scale (SUS) questionnaire and ease-of-use (EoU) assessment were performed. FINDINGS: 7471 participants were included in the analysis. Sensitivities across Ag-RDTs ranged from 70·4%-90·1%, specificities were above 97·2% for all Ag-RDTs but one (93·1%).Ag-RDTs, Mologic, Bionote, Standard Q, showed diagnostic accuracy in line with WHO targets (> 80% sensitivity, > 97% specificity). All tests showed high sensitivity in the first three days after symptom onset (≥87·1%) and in individuals with viral loads≥ 6 log10SARS-CoV2 RNA copies/mL (≥ 88·7%). Usability varied, with Rapigen, Bionote and Standard Q reaching very good scores; 90, 88 and 84/100, respectively. INTERPRETATION: Variability in test performance is partially explained by variable viral loads in population evaluated over the course of the pandemic. All Ag-RDTs reach high sensitivity early in the disease and in individuals with high viral loads, supporting their role in identifying transmission relevant infections. For easy-to-use tests, performance shown will likely be maintained in routine implementation. FUNDING: Ministry of Science, Research and Arts, State of Baden-Wuerttemberg, Germany, internal funds from Heidelberg University Hospital, University Hospital Charité - Universitätsmedizin Berlin, UK Department of International Development, WHO, Unitaid.

Parity and gonotrophic discordance of females of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in the city of São Paulo, SP, Brazil.

The objective of this study was to assess the parity, presence of blood in the stomach, and the gonotrophic discordance of females of Aedes aegypti and Aedes albopictus captured in two areas of the city of São Paulo. The captures were undertaken monthly, by aspiration, in the period from January, 2015 to August, 2017. All the females of the two species had their midguts and ovaries dissected to determine the presence of blood and the parity/stage of maturation. With regard to parity, 27% and 34% of the females of Ae. aegypti and Ae. albopictus, respectively, were parous or were in advanced stages of the development of their ovaries (33% and 27%, respectively). The larger part of the females of Ae. aegypti and Ae. albopictus contained blood in their stomachs (77% and 60%, respectively), beyond which 36% and 27% of the females of Ae. aegypti and Ae. albopictus, respectively, were in gonotrophic discordance. Our results indicate favorable conditions in the study areas because of the presence of parous females. Moreover, this frequent and multiple contact of Ae. aegypti and Ae. albopictus females with vertebrate hosts, such as humans, increases the possibility of transmitting the viruses they may be carrying.