scholarly journals Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

2021 ◽  
Vol 8 (7) ◽  
pp. 210530
Author(s):  
Julia R. Gog ◽  
Edward M. Hill ◽  
Leon Danon ◽  
Robin N. Thompson
Keyword(s):  
Mathematical Model ◽  
Clinical Trial ◽  
Immune Response ◽  
Simple Model ◽  
Selection Pressure ◽  
Heterogeneous Population ◽  
Reproduction Ratio ◽  
Contact Rates ◽  
Vaccination Campaigns ◽  
The Impact

As a countermeasure to the SARS-CoV-2 pandemic, there has been swift development and clinical trial assessment of candidate vaccines, with subsequent deployment as part of mass vaccination campaigns. However, the SARS-CoV-2 virus has demonstrated the ability to mutate and develop variants, which can modify epidemiological properties and potentially also the effectiveness of vaccines. The widespread deployment of highly effective vaccines may rapidly exert selection pressure on the SARS-CoV-2 virus directed towards mutations that escape the vaccine-induced immune response. This is particularly concerning while infection is widespread. By developing and analysing a mathematical model of two population groupings with differing vulnerability and contact rates, we explore the impact of the deployment of vaccines among the population on the reproduction ratio, cases, disease abundance and vaccine escape pressure. The results from this model illustrate two insights: (i) vaccination aimed at reducing prevalence could be more effective at reducing disease than directly vaccinating the vulnerable; (ii) the highest risk for vaccine escape can occur at intermediate levels of vaccination. This work demonstrates a key principle: the careful targeting of vaccines towards particular population groups could reduce disease as much as possible while limiting the risk of vaccine escape.

scholarly journals Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

2021 ◽  
Author(s):  
Julia R. Gog ◽  
Edward M. Hill ◽  
Leon Danon ◽  
Robin Thompson
Keyword(s):  
Mathematical Model ◽  
Clinical Trial ◽  
Immune Response ◽  
Simple Model ◽  
Selection Pressure ◽  
Heterogeneous Population ◽  
Population Groups ◽  
Contact Rates ◽  
Vaccination Campaigns ◽  
The Impact

AbstractAs a counter measure to the SARS-CoV-2 pandemic there has been swift development and clinical trial assessment of candidate vaccines, with subsequent deployment as part of mass vaccination campaigns. However, the SARS-CoV-2 virus has demonstrated the ability to mutate and develop variants, which can modify epidemiological properties and potentially also the effectiveness of vaccines.The widespread deployment of highly effective vaccines may rapidly exert selection pressure on the SARS-CoV-2 virus directed towards mutations that escape the vaccine induced immune response. This is particularly concerning whilst infection is widespread. By developing and analysing a mathematical model of two population groupings with differing vulnerability and contact rates, we explore the impact of the deployment of vaccine amongst the population on R, cases, disease abundance and vaccine escape pressure.The results from this model illustrate two insights (i) vaccination aimed at reducing prevalence could be more effective at reducing disease than directly vaccinating the vulnerable; (ii) the highest risk for vaccine escape can occur at intermediate levels of vaccination. This work demonstrates a key principle that the careful targeting of vaccines towards particular population groups could reduce disease as much as possible whilst limiting the risk of vaccine escape.

scholarly journals The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout

2021 ◽  
Author(s):  
Alexandra Teslya ◽  
Ganna Rozhnova ◽  
Thi Mui Pham ◽  
Daphne van Wees ◽  
Hendrik Nunner ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Transmission Model ◽  
Cumulative Number ◽  
Vaccination Rates ◽  
Contact Rates ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Vaccination Campaigns ◽  
The Impact

Abstract Mass vaccination campaigns against SARS-CoV-2 are under way in many countries with the hope that increasing vaccination coverage will enable reducing current physical distancing measures. Compliance with these measures is waning, while more transmissible virus variants such as B.1.1.7 have emerged. Using SARS-CoV-2 transmission model we investigated the impact of the feedback between compliance, the incidence of infection, and vaccination coverage on the success of a vaccination programme in the population where waning of compliance depends on vaccine coverage. Our results suggest that the combination of fast waning compliance, slow vaccination rates, and more transmissible variants may result in a higher cumulative number of infections than in a situation without vaccination. These adverse effects can be alleviated if vaccinated individuals do not revert to pre-pandemic contact rates, and if non-vaccinated individuals remain compliant with physical distancing measures. Both require convincing, clear and appropriately targeted communication strategies by public health authorities.

scholarly journals The impact of caudally administrated tramadol on immune response and analgesic efficacy for pediatric patients: a comparative randomized clinical trial

2018 ◽  
Vol 31 (3) ◽  
pp. 206 ◽  
Author(s):  
Jehan Ahmed Sayed ◽  
Sayed Kaoud Abd Elshafy ◽  
Emad Zareif Kamel ◽  
Mohamed Amir Fathy Riad ◽  
Amal Ahmed Mahmoud ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Immune Response ◽  
Randomized Clinical Trial ◽  
Pediatric Patients ◽  
Analgesic Efficacy ◽  
The Impact

scholarly journals Predicting the severity of disease progression in COVID-19 at the individual and population level: A mathematical model

2021 ◽  
Author(s):  
Narendra Chirmule ◽  
Pradip Nair ◽  
Bela Desai ◽  
Ravindra Khare ◽  
Vivek Nerurkar ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Immune Response ◽  
Clinical Outcome ◽  
Disease Progression ◽  
Neutralizing Antibodies ◽  
Complex Disease ◽  
Population Level ◽  
Immunological Parameters ◽  
Individual Level ◽  
The Impact

ABSTRACTThe impact of COVID-19 disease on health and economy has been global, and the magnitude of devastation is unparalleled in modern history. Any potential course of action to manage this complex disease requires the systematic and efficient analysis of data that can delineate the underlying pathogenesis. We have developed a mathematical model of disease progression to predict the clinical outcome, utilizing a set of causal factors known to contribute to COVID-19 pathology such as age, comorbidities, and certain viral and immunological parameters. Viral load and selected indicators of a dysfunctional immune response, such as cytokines IL-6 and IFNα, which contribute to the cytokine storm and fever, parameters of inflammation d-dimer and ferritin, aberrations in lymphocyte number, lymphopenia, and neutralizing antibodies were included for the analysis. The model provides a framework to unravel the multi-factorial complexities of the immune response manifested in SARS-CoV-2 infected individuals. Further, this model can be valuable to predict clinical outcome at an individual level, and to develop strategies for allocating appropriate resources to mitigate severe cases at a population level.

scholarly journals The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout

2021 ◽  
Author(s):  
Alexandra Teslya ◽  
Ganna Rozhnova ◽  
Thi Mui Pham ◽  
Daphne van Wees ◽  
Hendrik Nunner ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Transmission Model ◽  
Cumulative Number ◽  
Vaccination Rates ◽  
Contact Rates ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Vaccination Campaigns ◽  
The Impact

Abstract Mass vaccination campaigns against SARS-CoV-2 are under way in many countries with the hope that increasing vaccination coverage will enable reducing current physical distancing measures. Compliance with these measures is waning, while more transmissible virus variants such as B.1.1.7 have emerged. Using SARS-CoV-2 transmission model we investigated the impact of the feedback between compliance, the incidence of infection, and vaccination coverage on the success of a vaccination programme in the population where waning of compliance depends on vaccine coverage. Our results suggest that the combination of fast waning compliance, slow vaccination rates, and more transmissible variants may result in a higher cumulative number of infections than in a situation without vaccination. These adverse effects can be alleviated if vaccinated individuals do not revert to pre-pandemic contact rates, and if non-vaccinated individuals remain compliant with physical distancing measures. Both require convincing, clear and appropriately targeted communication strategies by public health authorities.

scholarly journals Mathematical Analysis and Clinical Implications of an HIV Model with Adaptive Immunity

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Jaouad Danane ◽  
Karam Allali
Keyword(s):  
Mathematical Model ◽  
Immune Response ◽  
Steady State ◽  
Adaptive Immunity ◽  
Reproduction Number ◽  
Adaptive Immune Response ◽  
Hiv Model ◽  
Adaptive Immune ◽  
The Impact ◽  
Ctl Immune Response

In this paper, a mathematical model describing the human immunodeficiency virus (HIV) pathogenesis with adaptive immune response is presented and studied. The mathematical model includes six nonlinear differential equations describing the interaction between the uninfected cells, the exposed cells, the actively infected cells, the free viruses, and the adaptive immune response. The considered adaptive immunity will be represented by cytotoxic T-lymphocytes cells (CTLs) and antibodies. First, the global stability of the disease-free steady state and the endemic steady states is established depending on the basic reproduction number R0, the CTL immune response reproduction number R1z, the antibody immune response reproduction number R1w, the antibody immune competition reproduction number R2w, and the CTL immune response competition reproduction number R3z. On the other hand, different numerical simulations are performed in order to confirm numerically the stability for each steady state. Moreover, a comparison with some clinical data is conducted and analyzed. Finally, a sensitivity analysis for R0 is performed in order to check the impact of different input parameters.

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

The Impact of Plant Bioactive Compounds on Aging and Fertility of Diverse Organisms: A Review

2020 ◽  
Vol 20 (13) ◽  
pp. 1287-1299
Author(s):  
Muhammad Akram Mohd Noordin ◽  
Mahanem Mat Noor ◽  
Wan Mohd Aizat
Keyword(s):  
Clinical Trial ◽  
Bioactive Compounds ◽  
Defense Mechanisms ◽  
Healthy Aging ◽  
Antioxidant Defense ◽  
Senior Citizens ◽  
Aging Population ◽  
Human Clinical Trial ◽  
Fertility Reduction ◽  
The Impact

It is expected that in 2050, there will be more than 20% of senior citizens aged over 60 years worldwide. Such alarming statistics require immediate attention to improve the health of the aging population. Since aging is closely related to the loss of antioxidant defense mechanisms, this situation eventually leads to numerous health problems, including fertility reduction. Furthermore, plant extracts have been used in traditional medicine as potent antioxidant sources. Although many experiments had reported the impact of various bioactive compounds on aging or fertility, there is a lack of review papers that combine both subjects. In this review, we have collected and discussed various bioactive compounds from 26 different plant species known to affect both longevity and fertility. These compounds, including phenolics and terpenes, are mostly involved in the antioxidant defense mechanisms of diverse organisms such as rats, mites, fruit flies, roundworms, and even roosters. A human clinical trial should be considered in the future to measure the effects of these bioactive compounds on human health and longevity. Ultimately, these plant-derived compounds could be developed into health supplements or potential medical drugs to ensure a healthy aging population.

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