Communicable Disease

2021 ◽  
pp. 205-233
Author(s):  
James Wilson
Keyword(s):  
Natural Selection ◽  
Case Studies ◽  
Communicable Disease ◽  
Herd Immunity ◽  
Public Trust ◽  
Ecological Perspective ◽  
Drug Resistant ◽  
Vaccination Policy ◽  
Disease Eradication ◽  
Causal Complexity

This chapter examines the idea of contagion—of risk magnification and modulation through networks. The chapter examines three case studies, each of which raises different questions about the interplay of causal complexity, performativity, and policymaking: vaccination policy, drug resistant infections, and disease eradication. In vaccination policy, achieving herd immunity is often crucial, but attempts to do this are heavily dependent on public trust. Drug resistant infections arise, among other causes, through the inevitable impact of natural selection, and so require a shift towards an ecological perspective on disease. Finally, the possibility of disease eradication poses important questions about when and how to ensure that susceptible health threats are systematically and permanently removed from the environment.

The Causal Structure of Natural Selection

2021 ◽  
Author(s):  
Charles H. Pence
Keyword(s):  
Natural Selection ◽  
Case Studies ◽  
Genetic Drift ◽  
Evolutionary Theory ◽  
Causal Structure ◽  
Philosophy Of Biology ◽  
Philosophy Of Physics ◽  
Potential Value ◽  
Multi Level ◽  
Evolutionary Explanations

Recent arguments concerning the nature of causation in evolutionary theory, now often known as the debate between the 'causalist' and 'statisticalist' positions, have involved answers to a variety of independent questions – definitions of key evolutionary concepts like natural selection, fitness, and genetic drift; causation in multi-level systems; or the nature of evolutionary explanations, among others. This Element offers a way to disentangle one set of these questions surrounding the causal structure of natural selection. Doing so allows us to clearly reconstruct the approach that some of these major competing interpretations of evolutionary theory have to this causal structure, highlighting particular features of philosophical interest within each. Further, those features concern problems not exclusive to the philosophy of biology. Connections between them and, in two case studies, contemporary metaphysics and philosophy of physics demonstrate the potential value of broader collaboration in the understanding of evolution.

scholarly journals Physical interactions reduce the power of natural selection in growing yeast colonies

2018 ◽  
Vol 115 (45) ◽  
pp. 11448-11453 ◽  
Author(s):  
Andrea Giometto ◽  
David R. Nelson ◽  
Andrew W. Murray
Keyword(s):  
Natural Selection ◽  
Continuum Model ◽  
Microbial Populations ◽  
Mechanical Forces ◽  
Time Varying ◽  
Drug Resistant ◽  
Yeast Strains ◽  
Physical Interactions ◽  
Varying Environments ◽  
Doubling Times

Microbial populations often assemble in dense populations in which proliferating individuals exert mechanical forces on the nearby cells. Here, we use yeast strains whose doubling times depend differently on temperature to show that physical interactions among cells affect the competition between different genotypes in growing yeast colonies. Our experiments demonstrate that these physical interactions have two related effects: they cause the prolonged survival of slower-growing strains at the actively-growing frontier of the colony and cause faster-growing strains to increase their frequency more slowly than expected in the absence of physical interactions. These effects also promote the survival of slower-growing strains and the maintenance of genetic diversity in colonies grown in time-varying environments. A continuum model inspired by overdamped hydrodynamics reproduces the experiments and predicts that the strength of natural selection depends on the width of the actively growing layer at the colony frontier. We verify these predictions experimentally. The reduced power of natural selection observed here may favor the maintenance of drug-resistant cells in microbial populations and could explain the apparent neutrality of interclone competition within tumors.

scholarly journals Prevalence of mumps antibodies in the Israeli population in relation to mumps vaccination policy and incidence of disease

2007 ◽  
Vol 136 (5) ◽  
pp. 688-693 ◽  
Author(s):  
Kh. MUHSEN ◽  
Y. ABOUDY ◽  
E. MENDELSON ◽  
M. S. GREEN ◽  
D. COHEN
Keyword(s):  
High School Students ◽  
Herd Immunity ◽  
Population Sample ◽  
Vaccination Policy ◽  
Birth Cohorts ◽  
Mmr Vaccine ◽  
School Students ◽  
Military Recruits ◽  
Israeli Population ◽  
Mumps Antibodies

SUMMARYWe examined the prevalence of mumps antibodies in the Israeli population in relation to mumps vaccination policy and past and subsequent incidence of disease. The levels of specific IgG antibodies against mumps were tested in 3330 residual sera collected during 1997–1998 from an age-stratified population sample. Against the background of a consistent MMR vaccination coverage of >90%, the age- and sex-adjusted seropositivity to mumps was 77·0%. No significant differences between genders were found. Seropositivity in the 10–13 years age group, born just before the introduction of the MMR vaccine, was the lowest (59%). These birth cohorts were the target of an outbreak of mumps in 2005 that occurred among high-school students and military recruits. A trend of waning immunity was observed between the first and second vaccine doses. The seroepidemiological data demonstrate that immunity levels below the herd immunity threshold, along with social mixing and crowded conditions facilitated the occurrence of mumps outbreaks. Periodical serosurveys are an essential component in the evaluation of the vaccination policy against mumps.

scholarly journals Overcoming COVID-19 vaccination resistance when alternative policies affect the dynamics of conformism, social norms, and crowding out

2021 ◽  
Vol 118 (25) ◽  
pp. e2104912118
Author(s):  
Katrin Schmelz ◽  
Samuel Bowles
Keyword(s):  
Herd Immunity ◽  
Crowding Out ◽  
Individual Freedom ◽  
Panel Survey ◽  
Vaccination Policy ◽  
Vaccine Acceptance ◽  
Policy Makers ◽  
Large Panel ◽  
Negative Effect ◽  
Broad Policy

What is an effective vaccination policy to end the COVID-19 pandemic? We address this question in a model of the dynamics of policy effectiveness drawing upon the results of a large panel survey implemented in Germany during the first and second waves of the pandemic. We observe increased opposition to vaccinations were they to be legally required. In contrast, for voluntary vaccinations, there was higher and undiminished support. We find that public distrust undermines vaccine acceptance, and is associated with a belief that the vaccine is ineffective and, if enforced, compromises individual freedom. We model how the willingness to be vaccinated may vary over time in response to the fraction of the population already vaccinated and whether vaccination has occurred voluntarily or not. A negative effect of enforcement on vaccine acceptance (of the magnitude observed in our panel or even considerably smaller) could result in a large increase in the numbers that would have to be vaccinated unwillingly in order to reach a herd-immunity target. Costly errors may be avoided if policy makers understand that citizens’ preferences are not fixed but will be affected both by the crowding-out effect of enforcement and by conformism. Our findings have broad policy applicability beyond COVID-19 to cases in which voluntary citizen compliance is essential because state capacities are limited and because effectiveness may depend on the ways that the policies themselves alter citizens’ beliefs and preferences.

scholarly journals Relief After COVID-19 Vaccination: A Doubtful or Evident Outcome?

2022 ◽  
Vol 8 ◽  
Author(s):  
Mohammed Khaled Al-Hanawi ◽  
Noor Alshareef ◽  
Rehab H. El-Sokkary
Keyword(s):  
Herd Immunity ◽  
Public Confidence ◽  
Multivariable Logistic Regression Analysis ◽  
Severe Reaction ◽  
Vaccination Policy ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Post Vaccination ◽  
Related Information ◽  
Mandatory Vaccination

Background: Since development of the first COVID-19 vaccine, the landscape of public confidence in these vaccines is uncertain. Building confidence is crucial for better preparedness of future pandemics. Following the mandatory COVID-19 vaccination policy in the country, the aim of this study was to examine whether the Saudi public feels relieved post-vaccination and to identify the factors predicting such relief.Methods: An online cross-sectional survey was conducted in July 2021 among COVID-19 vaccine recipients in Saudi Arabia. A multivariable logistic regression analysis was employed to examine and identify the variables associated with feeling relieved post-vaccination.Results: Most of the respondents (66%) stated feeling more relieved post-vaccination. Male gender [adjusted odds ratio (AOR): 1.380; 95% confidence interval (CI): 0.981–1.943], being a student (AOR: 3.902; 95% CI: 1.674–9.096), and received two doses of the vaccine (AOR: 2.278; 95% CI: 1.630–3.182) were associated with feeling more relieved after getting vaccinated. Respondents who were anxious about the vaccine before receiving it (AOR: 0.220; 95% CI: 0.160–0.302), and experienced a severe reaction after vaccination (AOR: 0.288; 95% CI: 0.165–0.504) had lower odds of feeling relieved post-vaccination. Respondents who relied on social media as the main source of vaccine-related information and those having no information about the vaccine were also less likely to feel relieved post-vaccination.Conclusions: Individuals' attitudes toward COVID-19 vaccines may not necessarily alter post-vaccination. Although mandatory vaccination policies can significantly contribute to achieving herd immunity, public confidence toward vaccines might be eroded, which could in turn impose significant challenges in future pandemics efforts.

Revisiting the stages of the policy cycle

2017 ◽  
Author(s):  
Mike Rayner ◽  
Kremlin Wickramasinghe ◽  
Julianne Williams ◽  
Karen McColl ◽  
Shanthi Mendis
Keyword(s):  
Case Studies ◽  
Communicable Disease ◽  
Theoretical Background ◽  
Linear Process ◽  
Policy Cycle ◽  
Specific Context ◽  
Policy Makers ◽  
And Control ◽  
Non Communicable Disease

This final chapter argues that the policy cycle should be seen as just that—a cycle, rather than a linear process with a defined start and finish. To generate effective policies, the stages need to be revisited over time. In revisiting these steps, it will be necessary to ask new questions about the problem and the solutions. The chapter includes case studies that illustrate how non-communicable disease (NCD) prevention and control interventions do not always follow the four steps of the policy cycle in a linear process. This chapter emphasizes that NCDs are multifactorial conditions with complex causal webs that require a sophisticated mix of solutions that reflect the specific context. The theoretical background, practical pointers, and case studies from this book should help to equip policy-makers, researchers, health advocates, and students with the knowledge and tools required to reduce the burden of death and disability from NCDs.

The Power of Natural Selection: A Guided Investigation of Three Case Studies

2010 ◽  
Vol 72 (2) ◽  
pp. 104-109
Author(s):  
William Beachly
Keyword(s):  
Natural Selection ◽  
Case Studies ◽  
College Freshmen ◽  
Quantitative Approach ◽  
Cranial Capacity ◽  
Algebraic Formula

I describe a quantitative approach to three case studies in evolution that can be used to challenge college freshmen to explore the power of natural selection and ask questions that foster a deeper understanding of its operation and relevance. Hemochromatosis, the peppered moth, and hominid cranial capacity are investigated with a common algebraic formula that illustrates the application of mathematics in biology.

scholarly journals How Can Vaccines Contribute to Solving the Antimicrobial Resistance Problem?

mBio ◽  
2016 ◽  
Vol 7 (3) ◽  
Author(s):  
Marc Lipsitch ◽  
George R. Siber
Keyword(s):  
Antimicrobial Resistance ◽  
Herd Immunity ◽  
Empirical Therapy ◽  
Clinical Syndrome ◽  
Drug Resistant ◽  
Target Species ◽  
Selection For ◽  
Research And Policy ◽  
Do So

ABSTRACT There is a growing appreciation for the role of vaccines in confronting the problem of antimicrobial resistance (AMR). Vaccines can reduce the prevalence of resistance by reducing the need for antimicrobial use and can reduce its impact by reducing the total number of cases. By reducing the number of pathogens that may be responsible for a particular clinical syndrome, vaccines can permit the use of narrower-spectrum antibiotics for empirical therapy. These effects may be amplified by herd immunity, extending protection to unvaccinated persons in the population. Because much selection for resistance is due to selection on bystander members of the normal flora, vaccination can reduce pressure for resistance even in pathogens not included in the vaccine. Some vaccines have had disproportionate effects on drug-resistant lineages within the target species, a benefit that could be more deliberately exploited in vaccine design. We describe the effects of current vaccines in controlling AMR, survey some vaccines in development with the potential to do so further, and discuss strategies to amplify these benefits. We conclude with a discussion of research and policy priorities to more fully enlist vaccines in the battle against AMR.

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