EV Charging Behavior Under Lockdown: A Multi-Method Comparison

The COVID-19 pandemic has affected human behavior drastically in various ways, including commuter patterns and traffic volumes. This paper investigates how the COVID-19 outbreak has changed the user habits and utilization patterns at public electric vehicle service equipment (EVSE). More than 7,300 charging sessions collected at 54 public Level 2 charging stations across the State of Rhode Island were analyzed using a multi-method approach comparing charging events from two time periods, before and during the pandemic. The study shows that charging behavior has changed significantly since the COVID-19 outbreak. We found that the energy consumption, charging duration, distance from home, and charging frequency decreased significantly during the pandemic. Additionally, the study discovered a relationship between the observation period and the day of the charging session. During the pandemic, charging on Sundays has become significantly more important for users than charging between Monday and Friday. We provide important insights for policymakers about how the COVID-19 pandemic has changed electric vehicle user charging behavior and demand. © 2022 IISE Annual Conference and Expo 2022. All rights reserved.

A method comparison study of the high throughput automated HISCL® SARS-CoV-2 antigen assay using nasopharyngeal swab samples from symptomatic and asymptomatic subjects against conventional RT-PCR.

Our study aim was to evaluate the performance of the automated Sysmex HISCL® severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen assay against reverse-transcription polymerase chain reaction (RT-PCR). We tested 277 remnant frozen nasopharyngeal swab samples, stored in universal transport medium (UTM), yielding a sensitivity of 94.9% against historical RT-PCR results with cycle threshold (Ct ) < 30, and a sensitivity of 76.7% for Ct < 35, and specificity of 100% (all Ct values) confirming compatibility of UTM-diluted samples with the assay system. Thereafter, we prospectively collected 141 nasopharyngeal swab samples in UTM from healthcare workers and 1369 paired swabs (400 UTM; 969 dry) from individuals at a public health testing center, with the first swab (UTM) reserved for RT-PCR, yielding a positivity rate of 4.6%. HISCL assay performance using UTM swabs was superior to dry swabs, with a sensitivity of 100% (95% confidence interval [CI] 71.5%-100%) at Ct < 30 versus 92.3% (95%CI 81.5%-97.9%), and a specificity of 99.3% (95% CI 98.1-99.89) against 83.3% (95%CI 80.7%-85.6%). We conclude that this antigen assay is suitable for high throughput facilities where the primary indication for testing is to rule out infection with low RT-PCR Ct values (proxy for high viral loads) to curb viral spread.

A method comparison of three immunoassays for detection of neutralizing antibodies against SARS-CoV-2 receptor-binding domain in individuals with adenovirus type-5-vectored COVID-19 vaccination.

OBJECTIVE: Detecting neutralizing antibodies targeting receptor-binding domain (RBD) is important for the assessment of humoral protection and vaccine efficacy after vaccination. We compared the performance of three surrogate immunoassays for detection of neutralizing antibodies targeting RBD. METHODS: We analyzed 115 serum samples obtained from individuals with Ad5-vectored COVID-19 vaccination using two competitive enzyme-linked immunosorbent assays (Wantai BioPharm and Synthgene Medical Technology) and one competitive chemiluminescence assay (YHLO Biotech). Performance evaluation and methodology comparison were performed according to the Clinical and Laboratory Standards Institute related guidelines. RESULTS: The precision met the manufacturers' statements. The linear range of the WANTAI was 0.0625-0.545 U/ml and the YHLO was 0.260-242.4 U/ml. The WANTAI's limit of blank (LoB) and limit of detection (LoD) were 0.03 and 0.06 U/ml, respectively. The YHLO's LoB and LoD were 0.048 and 0.211 U/ml, respectively. The correlations of semi-quantitative results of Synthgene with quantitative results of YHLO (ρ = 0.566) and WANTAI (ρ = 0.512) were medium. For YHLO and WANTAI, there was a good agreement (0.62) and a strong correlation (ρ = 0.931). Passing-Bablok analysis and Bland-Altman plot showed a positive bias (112.3%) of the YHLO compared to the WANTAI. The exclusion of samples >50 U/ml did not decrease bias. CONCLUSION: These findings contribute to a deeper understanding of surrogate viral neutralization assays and provide useful data for future comparison studies.

Antibodies against SARS-CoV-2 Time Course in Patients and Vaccinated Subjects: An Evaluation of the Harmonization of Two Different Methods.

The time course of antibodies against SARS-CoV-2 is not yet well elucidated, especially in people who underwent a vaccination campaign. In this study, we measured the antibodies anti-S1 and anti-RBD with two different methods, both in patients and in vaccinated subjects. One hundred and eight specimens from 48 patients with COVID-19 (time from the onset of symptoms from 3 to 368 days) and 60 specimens from 20 vaccinated subjects (collected after 14 days from the first dose, 14 days and 3 months after a second dose of Comirnaty) were evaluated. We used an ELISA method that measured IgG against anti-Spike 1, and a chemiluminescence immunoassay that measured IgG anti-RBD. In the patients, the antibodies concentrations tended to decline after a few months, with both the methods, but they persisted relatively high up to nearly a year after the symptoms. In the vaccinated subjects, the antibodies were already detectable after the first dose, but after the booster, they showed a significant increase. However, the decrease was rapid, given that 3 months after the second vaccination, they were reduced to less than a quarter. The conversion of the results into BAU units improves the relationship between the two methods. However, in the vaccinated subjects, there was no evidence of proportional error after the conversion, while in the patients, the difference between the two methods remained significant.

Multicentre Performance Evaluation of the Elecsys Anti-SARS-CoV-2 Immunoassay as an Aid in Determining Previous Exposure to SARS-CoV-2.

INTRODUCTION: We performed a multicentre evaluation of the Elecsys® Anti-SARS-CoV-2 immunoassay (Roche Diagnostics), an assay utilising a recombinant protein representing the nucleocapsid (N) antigen, for the in vitro qualitative detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Specificity was evaluated using serum/plasma samples from blood donors and routine diagnostic specimens collected before September 2019 (i.e., presumed negative for SARS-CoV-2-specific antibodies); sensitivity was evaluated using samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection. Point estimates and 95% confidence intervals (CIs) were calculated. Method comparison was performed versus commercially available assays. RESULTS: Overall specificity for the Elecsys Anti-SARS-CoV-2 immunoassay (n = 9575) was 99.85% (95% CI 99.75-99.92): blood donors (n = 6714; 99.82%), routine diagnostic specimens (n = 2861; 99.93%), pregnant women (n = 2256; 99.91%), paediatric samples (n = 205; 100.00%). The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated significantly higher specificity versus LIAISON SARS-CoV-2 S1/S2 IgG (99.71% vs. 98.48%), EUROIMMUN Anti-SARS-CoV-2 IgG (100.00% vs. 94.87%), ADVIA Centaur SARS-CoV-2 Total (100.00% vs. 87.32%) and iFlash SARS-CoV-2 IgM (100.00% vs. 99.58%) assays, and comparable specificity to ARCHITECT SARS-CoV-2 IgG (99.75% vs. 99.65%) and iFlash SARS-CoV-2 IgG (100.00% vs. 100.00%) assays. Overall sensitivity for Elecsys Anti-SARS-CoV-2 immunoassay samples drawn at least 14 days post-PCR confirmation (n = 219) was 93.61% (95% CI 89.51-96.46). No statistically significant differences in sensitivity were observed between the Elecsys Anti-SARS-CoV-2 immunoassay versus EUROIMMUN Anti-SARS-CoV-2 IgG (90.32% vs. 95.16%) and ARCHITECT SARS-CoV-2 IgG (84.81% vs. 87.34%) assays. The Elecsys Anti-SARS-CoV-2 immunoassay showed significantly lower sensitivity versus ADVIA Centaur SARS-CoV-2 Total (85.19% vs. 95.06%) and iFlash SARS-CoV-2 IgG (86.25% vs. 93.75%) assays, but significantly higher sensitivity versus the iFlash SARS-CoV-2 IgM assay (86.25% vs. 33.75%). CONCLUSION: The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated very high specificity and high sensitivity in samples collected at least 14 days post-PCR confirmation of SARS-CoV-2 infection, supporting its use to aid in determination of previous exposure to SARS-CoV-2.

Serum 25-hydroxyvitamin D measurement: Comparative evaluation of three automated immunoassays.

OBJECTIVES: the different analytical methods for measurement of serum 25-hydroxyvitamin D (25(OH)D) are not yet fully harmonized and no consensus exists on a threshold of 25(OH)D defining a deficiency status. In this study, we compared the results from the assays of serum 25(OH)D performed with three different methods to evaluate the presence of potential biases and how much these biases can influence the assignment of patients to specific 25(OH)D deficiency/sufficiency categories. DESIGN AND METHODS: Liaison 25(OH) Vitamin D Total (DiaSorin Liaison XL), Elecsys Vitamin D Total II (Roche Elecsys) and Lumipulse G25(OH) Vitamin D (Fujirebio Lumipulse G1200) were used. Methods comparability was established performing Passing-Bablok regression and Bland-Altman analysis to prove whether the differences found were lower than the preliminarily pre-established maximum acceptable bias. RESULTS: all Passing-Bablok regressions exhibited the presence of a proportional and constant systematic error. Bland-Altman analysis revealed biases well above the maximum acceptable bias, so the 25(OH)D concentrations measured were not comparable. To evaluate whether the three methods had the same ability to classify patients into different categories of vitamin D levels, we categorized results obtained by each method in reference classes. Lumipulse categorized most patients into the class with the lowest 25(OH)D concentrations (<20 ng/mL) whereas Elecsys ranked the lowest number. CONCLUSIONS: Liaison XL and Elecsys have shown good accuracy compared to Lumipulse in measuring 25(OH)D levels. Nevertheless, the assays were not interchangeable due to the lack of comparability of results as well as to the disagreement in classification of hormone deficiency or sufficiency.

A Comparative Analysis of Statistical Methods to Estimate the Reproduction Number in Emerging Epidemics, With Implications for the Current Coronavirus Disease 2019 (COVID-19) Pandemic.

BACKGROUND: As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues its rapid global spread, quantification of local transmission patterns has been, and will continue to be, critical for guiding the pandemic response. Understanding the accuracy and limitations of statistical methods to estimate the basic reproduction number, R0, in the context of emerging epidemics is therefore vital to ensure appropriate interpretation of results and the subsequent implications for control efforts. METHODS: Using simulated epidemic data, we assess the performance of 7 commonly used statistical methods to estimate R0 as they would be applied in a real-time outbreak analysis scenario: fitting to an increasing number of data points over time and with varying levels of random noise in the data. Method comparison was also conducted on empirical outbreak data, using Zika surveillance data from the 2015-2016 epidemic in Latin America and the Caribbean. RESULTS: We find that most methods considered here frequently overestimate R0 in the early stages of epidemic growth on simulated data, the magnitude of which decreases when fitted to an increasing number of time points. This trend of decreasing bias over time can easily lead to incorrect conclusions about the course of the epidemic or the need for control efforts. CONCLUSIONS: We show that true changes in pathogen transmissibility can be difficult to disentangle from changes in methodological accuracy and precision in the early stages of epidemic growth, particularly for data with significant over-dispersion. As localized epidemics of SARS-CoV-2 take hold around the globe, awareness of this trend will be important for appropriately cautious interpretation of results and subsequent guidance for control efforts.

Comparison of four high-throughput, automated immunoassays for the detection of SARS-CoV-2 antibodies.

BACKGROUND: A number of immunoassays have been developed to measure antibodies specific to SARS-CoV-2. More data is required on their comparability, particularly among those with milder infections and in the general practice population. The aim of this study was to compare four high-throughput automated anti-SARS-CoV-2 assays using samples collected from hospitalized patients and healthcare workers with confirmed SARS-CoV-2 infection. In addition, we collected general practice samples to compare antibody results and determine seroprevalence. METHODS: Samples were collected from 57 hospitalized patients and nine healthcare workers at 14 days and at 28 days following confirmed SARS-CoV-2 infection. Samples were also collected from 225 patients presenting to general practice. Four assays were used: Abbott Architect IgG, Beckman Coulter DxI 800 IgG, Roche Cobas e801 total antibody and Siemens Advia Centaur XPT total antibody. RESULTS: All four assays showed concordance at 14 days in 83.9% of hospitalized patients and in 66.7% of healthcare workers. All four assays showed concordance at 28 days in 88.4% of hospitalized patients and 77.8% of healthcare workers. The sensitivity to detect recent infection was higher for the IgG assays than the total assays. All four assays showed concordance of 95.1% in the general practice population. Seroprevalence ranged from 4.9 to 5.8% depending on the assay used. CONCLUSIONS: All four assays showed excellent comparability, but it may be possible to obtain a negative result for any of the anti-SARS-CoV-2 assays in patients with confirmed previous SARS-CoV-2 infection. An equivocal range would be useful for all anti-SARS-CoV-2 assays.

Point-of-care test system for detection of immunoglobulin-G and -M against nucleocapsid protein and spike glycoprotein of SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) epidemic continues to ravage the world. In epidemic control, dealing with a large number of samples is a huge challenge. In this study, a point-of-care test (POCT) system was successfully developed and applied for rapid and accurate detection of immunoglobulin-G and -M against nucleocapsid protein (anti-N IgG/IgM) and receptor-binding domain in spike glycoprotein (anti-S-RBD IgG/IgM) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Any one of the IgG/IgM found in a sample was identified as positive. The POCT system contains colloidal gold-based lateral flow immunoassay test strips, homemade portable reader, and certified reference materials, which detected anti-N and anti-S-RBD IgG/IgM objectively in serum within 15 min. Receiver operating characteristic curve analysis was used to determine the optimal cutoff values, sensitivity, and specificity. It exhibited equal to or better performances than four approved commercial kits. Results of the system and chemiluminescence immunoassay kit detecting 108 suspicious samples had high consistency with kappa coefficient at 0.804 (P < 0.001). Besides, the levels and alterations of the IgG/IgM in an inpatient were primarily investigated by the POCT system. Those results suggested the POCT system possess the potential to contribute to rapid and accurate serological diagnosis and epidemiological survey of COVID-19.

Two SARS-CoV-2 IgG immunoassays comparison and time-course profile of antibodies response.

INTRODUCTION: The persistence of circulating antibodies to SARS-CoV-2 infection is not yet well known. We compare the results of 2 automated systems for the determination of IgG against SARS CoV-2 and assess the time-course of the IgG response. METHODS: IgG were measured in 103 specimens of 55 patients with COVID-19 (time from the symptoms' onset: 3-187 days) using the automated tests "Abbott SARS-COV-2 IgG" and "MAGLUMI 2019-nCoV IgG". RESULTS: The 2 methods had a concordance of 90.3%, but the quantitative correlation, although significant, showed dispersed results. All the specimens resulted positive after 17 days. However, the median concentrations of IgG rapidly increased up to 20 days and decreased for Maglumi IgG while Abbott IgG showed a constant trend up to 85 days, and then slowly declined. CONCLUSIONS: The titer of IgG against SARS-CoV-2 may significantly and rapidly decrease, but with a very different time-course depending on the method used for the determination.

Comparison of test performance of commercial anti-SARS-CoV-2 immunoassays in serum and plasma samples.

BACKGROUND: For epidemiologic, social and economic reasons, assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection prevalence and immunity are important to adapt decisions to current demands. Hence, immunoassays for detection of anti-SARS-CoV-2 antibodies are introduced rapidly without requiring FDA emergency use authorization approval. Thus, evaluation of test performance predominantly relies on laboratories. This study aimed to evaluate the test performance of recently launched commercial immunoassays in serum and plasma samples. METHODS: 51 serum samples from 26 patients with confirmed SARS-CoV-2 infection after end of quarantine and 25 control patients were analyzed using anti-SARS-CoV-2 IgG immunoassays from Roche, Euroimmun and Epitope to assess diagnostic sensitivity and specificity. 20 matching pairs of serum and plasma samples were included to analyze comparability between different specimens. RESULTS: Overall, a diagnostic sensitivity of 92.3%, 96.2-100% and 100% with a respective diagnostic specificity of 100%, 100% and 84-86% for the immunoassays from Roche, Euroimmun and Epitope were determined. In total, 84-96% of samples were correctly classified as negative and 92.3-95.2% as positive. The level of concordance between plasma- and serum-based testing diverged between the assays (Epitope r2 = 0.97; Euroimmun r2 = 0.91; Roche r2 = 0.76). CONCLUSIONS: The immunoassays from Euroimmun and Roche revealed a higher specificity than the Epitope assay without a substantial drop of diagnostic sensitivity. Significant differences between plasma- and serum-based testing highlights the need for determination of appropriate cut-offs per specimen type. Hence, there is an urgent need for test harmonization and establishment of quality standards for an appropriate use of COVID-19 serological tests.