scholarly journals Population impact of SARS-CoV-2 variants with enhanced transmissibility and/or partial immune escape

2021 ◽  
Author(s):  
Mary Bushman ◽  
Rebecca Kahn ◽  
Bradford P. Taylor ◽  
Marc Lipsitch ◽  
William P. Hanage
Keyword(s):  
Mathematical Model ◽  
High Frequency ◽  
Immune Escape ◽  
Low Risk ◽  
Population Impact ◽  
Nonpharmaceutical Interventions ◽  
Induced Immunity ◽  
Do So

SummarySARS-CoV-2 variants of concern exhibit varying degrees of transmissibility and, in some cases, escape from infection- and vaccine-induced immunity. Much effort has been devoted to measuring these phenotypes, but predicting their impact on the course of the pandemic – especially that of immune escape – remains a challenge. Here, we use a mathematical model to simulate the dynamics of wildtype and variant strains of SARS-CoV-2 in the context of vaccine rollout and nonpharmaceutical interventions. We show that variants with enhanced transmissibility easily rise to high frequency, whereas partial immune escape, on its own, often fails to do so. However, when these phenotypes are combined, enhanced transmissibility can carry the variant to high frequency, at which point partial immune escape may limit the ability of vaccination to control the epidemic. Our findings suggest that moderate immune escape poses a low risk unless combined with a substantial increase in transmissibility.

scholarly journals COVID-19 vaccines that reduce symptoms but do not block infection need higher coverage and faster rollout to achieve population impact

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David A. Swan ◽  
Chloe Bracis ◽  
Holly Janes ◽  
Mia Moore ◽  
Laura Matrajt ◽  
...  
Keyword(s):  
Mathematical Model ◽  
No Reduction ◽  
King County ◽  
Symptomatic Disease ◽  
Population Impact ◽  
Susceptibility To Infection ◽  
Infection Susceptibility ◽  
Asymptomatic Infections ◽  
The U.S

AbstractTrial results for two COVID-19 vaccines suggest at least 90% efficacy against symptomatic disease (VEDIS). It remains unknown whether this efficacy is mediated by lowering SARS-CoV-2 infection susceptibility (VESUSC) or development of symptoms after infection (VESYMP). We aim to assess and compare the population impact of vaccines with different efficacy profiles (VESYMP and VESUSC) satisfying licensure criteria. We developed a mathematical model of SARS-CoV-2 transmission, calibrated to data from King County, Washington. Rollout scenarios starting December 2020 were simulated with combinations of VESUSC and VESYMP resulting in up to 100% VEDIS. We assumed no reduction of infectivity upon infection conditional on presence of symptoms. Proportions of cumulative infections, hospitalizations and deaths prevented over 1 year from vaccination start are reported. Rollouts of 1 M vaccinations (5000 daily) using vaccines with 50% VEDIS are projected to prevent 23–46% of infections and 31–46% of deaths over 1 year. In comparison, vaccines with 90% VEDIS are projected to prevent 37–64% of infections and 46–64% of deaths over 1 year. In both cases, there is a greater reduction if VEDIS is mediated mostly by VESUSC. The use of a “symptom reducing” vaccine will require twice as many people vaccinated than a “susceptibility reducing” vaccine with the same 90% VEDIS to prevent 50% of the infections and death over 1 year. Delaying the start of the vaccination by 3 months decreases the expected population impact by more than 50%. Vaccines which prevent COVID-19 disease but not SARS-CoV-2 infection, and thereby shift symptomatic infections to asymptomatic infections, will prevent fewer infections and require larger and faster vaccination rollouts to have population impact, compared to vaccines that reduce susceptibility to infection. If uncontrolled transmission across the U.S. continues, then expected vaccination in Spring 2021 will provide only limited benefit.

scholarly journals Population Impact of SARS-CoV-2 Variants with Enhanced Transmissibility and/or Partial Immune Escape

2021 ◽  
Author(s):  
Mary Bushman ◽  
Rebecca Kahn ◽  
Bradford P. Taylor ◽  
Marc Lipsitch ◽  
William P. Hanage
Keyword(s):  
Immune Escape ◽  
Population Impact

scholarly journals Perceived ethical misconduct: a survey of neuropsychology professionals in Mexico

2016 ◽  
Vol 9 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Paola Fonseca ◽  
Laiene Olabarrieta Landa ◽  
Ivan Panyavin ◽  
Xóchitl Angélica Ortiz Jiménez ◽  
Adriana Aguayo Arelis ◽  
...  
Keyword(s):  
Professional Practice ◽  
High Frequency ◽  
Professional Training ◽  
Clinical Care ◽  
Professional Relationships ◽  
Ethical Misconduct ◽  
And Training ◽  
Do So

Objective: To evaluate the frequency of perceived ethical misconduct in the practice of neuropsychology in Mexico. Method: One hundred fourteen psychologists answered a survey which assessed perceptions of ethical misconduct in four areas of professional practice in the field of neuropsychology.Results: The area of professional training contained the highest percentage of perception of ethical misconduct, followed by research and publications, clinical care, and professional relationships. Conclusion: The high frequency of ethical misconduct perceived by neuropsychology professionals in Mexico is a cause for concern. The results suggest the need to create and implement a system to make sure that professionals follow the ethics standards required by the profession, and to provide consequences for those who fail to do so. The profession of neuropsychology and training of professionals in the field must be regularized in the country, to reduce the frequency of future ethical misconducts.

Optimal H∞ Control of Structural Vibrations Using Shape Memory Alloy Actuators

1999 ◽  
Author(s):  
Jian Sun ◽  
Ali R. Shahin
Keyword(s):  
Mathematical Model ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Model Uncertainty ◽  
High Frequency ◽  
Structural Vibrations ◽  
Design Procedures ◽  
Sma Actuators ◽  
Temperature Dynamics ◽  
The Mathematical Model

Abstract This paper investigates robust control problem of structural vibrations using shape memory alloy (SMA) wires as actuators. The mathematical model for these SMA actuators is derived with emphasis in model uncertainty. The linearization of the relation between stress and temperature dynamics of SMA actuators is analyzed for active control. To handle the uncertainties caused by the linearization and the neglected high frequency dynamics, optimal H∞ control was employed to design a controller. An example is used to demonstrate the design procedures and the control system is tested in a nonlinear environment.

Modeling the Conditions for Microdroplets Formation and their Detachment from the Molten Metal on the Electrode

2021 ◽  
Vol 313 ◽  
pp. 1-7
Author(s):  
V.D. Sarychev ◽  
S.A. Solodsky ◽  
Sergey A. Nevskii ◽  
M.A. Kuznetsov ◽  
D.P. Ilyaschenko ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Molten Metal ◽  
High Frequency ◽  
Plasma Discharge ◽  
Pulse Action ◽  
Materials Processing ◽  
Physical Processes ◽  
Micro Scale ◽  
Physical Mechanisms ◽  
Frequency Pulse

Formation of nanostructure states on the surface of materials exposed to concentrated flows of energy is one of the relevant problems of modern materials processing. In the paper the authors describe the mechanism of the micro-scale droplets formation based on the study and modeling of the physical processes and technological aspects of the interaction between the heterogenic plasma flows and the molten substance at the electrode tip. The authors show new physical mechanisms and criteria for micro-and nanoparticles origination, develop a physical-mathematical model of the interaction between the molten metal and the plasma discharge with imposed high-frequency pulse action.

scholarly journals “Don’t Eat Me” Signals of Neuroblastoma by CD47 for Immune Escape: A Novel Prognostic Biomarker

Proceedings ◽  
2018 ◽  
Vol 2 (25) ◽  
pp. 1538
Author(s):  
Safiye Aktas ◽  
Ayse Pinar Ercetin Ozdemir ◽  
Efe Ozgur Serinan ◽  
Zekiye Altun ◽  
Nur Olgun
Keyword(s):  
High Risk ◽  
Immune Escape ◽  
Prognostic Biomarker ◽  
Immunohistochemical Analysis ◽  
Risk Groups ◽  
Genetic Alterations ◽  
High Risk Group ◽  
Low Risk ◽  
P Value ◽  
Mycn Amplification

Recent studies have shown that cancer cells can deceive phagocytosing macrophage cells through the CD47 protein which gives the message “don’t eat me” or “don’t kill me” to immune components. The efficacy of anti-CD47 treatment approach was shown in cancers such as, non-small cell lung cancer, non-Hodgkin lymphoma, ovarian cancer, and breast cancer. The studies on the immunobiology of neuroblastoma has increased as monoclonal antibody based immunotherapy has shown to be effective in high-risk patients such as anti disialoganglioside. Therefore, the aim of this study was to evaluate the levels of CD47 protein expression among neuroblastoma patients with different risk groups and genetic alterations. This study included paraffin-embedded tumor tissues of 66 neuroblastoma patients (28 girls, 38 boys) with an age range of 0.5 to 108 months with a mean value of 24.9 (±23.5). According to risk classifications 21 were at low risk (31, 8%), 24 were at intermediate risk (36, 4%) and 19 were at high-risk (28, 8%) groups. These samples were evaluated for MYCN amplification, 1p36 LOH, 11q23 deletion and 17q25 gain by real-time PCR. In addition, CD47 expression status (positive or negative) was detected by immunohistochemical analysis. All data was analyzed with Chi-Square and Mann-Whitney U non-parametric tests within SPSS program, version 22.0. p value lower than 0, 5 was found statistically significant. According to the results, patients at low risk did not express CD47, while patients at high-risk group were mostly expressing CD47 (p = 0.049). MYCN amplification positive patients were expressing CD47 protein (p = 0.046). Patients without 17q25 gain were found to be expressing CD47 protein (p = 0.006). In addition, CD47 expression was increasing as age was getting higher in terms of months (p = 0.018). The findings of this study suggest that positive expression pattern of CD47 may be a poor prognostic biomarker especially in high risk 17q gain negative neuroblastoma patients.

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