scholarly journals Extending upon: What effect might border screening have on preventing importation of COVID-19 compared with other infections? - Considering the additional effect of post-arrival isolation

2021 ◽  
Author(s):  
Declan Bays ◽  
Emma Bennett ◽  
Thomas James Ronald Finnie
Keyword(s):  
Simple Model ◽  
Extended Model ◽  
Detection Rates ◽  
Additional Requirement ◽  
Isolation Period

We recently described a simple model through which we assessed what effect subjecting travellers to a single on-arrival test might have on reducing risk of importing disease cases during simulated outbreaks of COVID-19, Influenza, SARS, and Ebola. We build upon this work to allow for the additional requirement that inbound travellers also undergo a period of self-isolation upon arrival, where upon completion the traveller is again tested for signs of infection prior to admission across the border. Prior results indicated that a single on-arrival test has the potential to detect 9% of travellers infected with COVID-19, compared to 35%, 10% and 3% for travellers infected with influenza, SARS, and Ebola respectively. Our extended model shows that testing administered after a 2-day isolation period may be able to detect up to 41%, 97%, 44% and 15% of COVID-19, Influenza, SARS, and Ebola infected travellers respectively. Longer self-isolation periods increase detection rates further, with an 8-day self-isolation period suggesting detection rates of up to 94%, 100%, 98% and 62% for travellers infected with COVID-19, Influenza, SARS, and Ebola respectively. These results therefore suggest that testing arrivals after an enforced period of self-isolation may present a reasonable method of protecting against case importation during international outbreaks.

scholarly journals ROLE OF REPEAT INFECTION IN THE DYNAMICS OF A SIMPLE MODEL OF WANING AND BOOSTING IMMUNITY

2021 ◽  
pp. 1-22
Author(s):  
LAURA F. STRUBE ◽  
MAYA WALTON ◽  
LAUREN M. CHILDS
Keyword(s):  
Simple Model ◽  
Secondary Infection ◽  
Dynamical Behavior ◽  
Stable Limit Cycle ◽  
Epidemiological Data ◽  
Small Region ◽  
Extended Model ◽  
Stable Limit ◽  
Bifurcation Structures ◽  
Repeat Infection

Some infectious diseases produce lifelong immunity while others only produce temporary immunity. In the case of short-lived immunity, the level of protection wanes over time and may be boosted upon re-exposure, via infection or vaccination. Previous work developed a simple model capturing waning and boosting immunity, known as the Susceptible-Infectious-Recovered-Waned-Susceptible (SIRWS) model, which exhibits rich dynamical behavior including supercritical and subcritical Hopf bifurcations among other structures. Here, we extend the bifurcation analyses of the SIRWS model to examine the influence of all parameters on these bifurcation structures. We show that the bistable region, involving both a stable fixed point and a stable limit cycle, exists only for a small region of biologically realistic parameter space. Furthermore, we contrast the SIRWS model with a modified version, where immune boosting may involve the occurrence of a secondary infection. Analysis of this extended model shows that oscillations and bistability, as found in the SIRWS model, depend on strong assumptions about infectivity and recovery rate from secondary infection. Understanding the dynamics of models of waning and boosting immunity is important for accurately assessing epidemiological data.

scholarly journals Does sampling saliva increase detection of SARS-CoV-2 by RT-PCR? Comparing saliva with oro-nasopharyngeal swabs

2020 ◽  
Author(s):  
Ozlem Akgun Dogan ◽  
Betsi Kose ◽  
Nihat Bugra Agaoglu ◽  
Jale Yildiz ◽  
Gizem Alkurt ◽  
...  
Keyword(s):  
Gold Standard ◽  
Viral Rna ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Standard Samples ◽  
Rna Detection ◽  
Detection Rates ◽  
Gold Standard Method ◽  
Non Invasive ◽  
Isolation Period

The gold standard method in the diagnosis of SARS-CoV-2 infection is the detection of viral RNA in nasopharyngeal sample by RT-PCR. Recently, saliva samples has been suggested as an alternative due to being fast, reliable and non-invasive, rather than nasopharyngeal samples. We compared RT-PCR results in nasopharyngeal, oro-nasopharyngeal and saliva samples of COVID-19 patients. 98 of 200 patients were positive in RT-PCR analysis performed before the hospitalization. In day 0, at least one sample was positive in 67% of 98 patients. Positivity rate was 83% for both oro-nasopharyngeal and nasopharyngeal samples, while it was 63% for saliva samples (p<0.001). On day 5, RT-PCR was performed in 59 patients, 34% had at least one positive result. The positivity rate was 55% for saliva and nasopharyngeal samples, while it was 60% for oro-nasopharyngeal samples. Our study shows that the sampling saliva does not increase the sensitivity of RT-PCR tests at early stages of infection. However, on 5th day, viral RNA detection rates in saliva were similar to nasopharyngeal and oro-nasopharyngeal samples. In conclusion, we suggest that, in patients receiving treatment, virus presence in saliva, in addition to the standard samples, is important to determine the isolation period and to control the transmission.

Different Forms of Work Satisfaction

1998 ◽  
Vol 3 (3) ◽  
pp. 209-218 ◽  
Author(s):  
André Büssing ◽  
Thomas Bissels
Keyword(s):  
Work Satisfaction ◽  
Preliminary Evidence ◽  
Qualitative Approach ◽  
Extended Model ◽  
Work Situation ◽  
Structured Interviews ◽  
Global Satisfaction ◽  
Evaluative Processes ◽  
The Right ◽  
Level Of Aspiration

The extended model of different forms of work satisfaction ( Büssing, 1991 ), originally proposed by Bruggemann (1974) , is suggested as a distinctive qualitative approach to work satisfaction. Six forms of work satisfaction—progressive, stabilized, resigned satisfaction, constructive, fixated, resigned dissatisfaction—are derived from the constellation of four constituent variables: comparison of the actual work situation and personal aspirations, global satisfaction, changes in level of aspiration, controllability at work. Preliminary evidence from semi-structured interviews with 46 nurses shows that the dynamic model is headed in the right direction (qualitative differentiation of consistently high propertions of satisfied employees, uncovering processes of person-work situation interaction). Qualitative methods demonstrated their usefulness in accessing underlying cognitive and evaluative processes of the forms, which are often neglected by traditional attitude-based satisfaction research.

Mutuality in Acculturation

2013 ◽  
Vol 221 (4) ◽  
pp. 205-213 ◽  
Author(s):  
Gabriel Horenczyk ◽  
Inga Jasinskaja-Lahti ◽  
David L. Sam ◽  
Paul Vedder
Keyword(s):  
Intergroup Relations ◽  
Extended Model ◽  
Psychological Study ◽  
Intergroup Interactions ◽  
Mutual Contact ◽  
Acculturation Model ◽  
Plural Societies ◽  
Perceptions And Expectations

This paper focuses on processes and consequences of intergroup interactions in plural societies, focusing primarily on majority-minority mutuality in acculturation orientations. We examine commonalities and differences among conceptualizations and models addressing issues of mutuality. Our review includes the mutual acculturation model ( Berry, 1997 ), the Interactive Acculturation Model (IAM – Bourhis et al., 1997 ), the Concordance Model of Acculturation (CMA – Piontkowski et al., 2002 ); the Relative Acculturation Extended Model (RAEM – Navas et al., 2005 ), and the work on acculturation discrepancies conducted by Horenczyk (1996 , 2000 ). We also describe a trend toward convergence of acculturation research and the socio-psychological study of intergroup relations addressing issues of mutuality in attitudes, perceptions, and expectations. Our review has the potential to enrich the conceptual and methodological toolbox needed for understanding and investigating acculturation in complex modern societies, where majorities and minorities, immigrants and nationals, are engaged in continuous mutual contact and interaction, affecting each other’s acculturative choices and acculturative expectations.

Chaos and secular cycles in a structurally simple model society

2012 ◽  
Author(s):  
Alexander Medvinsky ◽  
Alexey Rusakov
Keyword(s):  
Simple Model

A Simple Model of Changes in Lumbar Intervertebral Angles During Sagittal Torso Flexion

2011 ◽  
Author(s):  
Riley E. Splittstoesser ◽  
Greg G. Knapik ◽  
William S. Marras
Keyword(s):  
Simple Model

Discussion of the band structure effects on thermoemission as deduced from a simple model

1976 ◽  
Vol 37 (2) ◽  
pp. 149-158 ◽  
Author(s):  
A.K. Bhattacharjee ◽  
B. Caroli ◽  
D. Saint-James
Keyword(s):  
Simple Model ◽  
Band Structure
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