scholarly journals Targeted vaccination and the speed of SARS-CoV-2 adaptation

2022 ◽  
Vol 119 (3) ◽  
pp. e2110666119
Author(s):  
Sylvain Gandon ◽  
Sébastien Lion
Keyword(s):  
Disease Burden ◽  
Rate Of Change ◽  
Cumulative Number ◽  
Vaccination Strategies ◽  
Viral Adaptation ◽  
Speed Up ◽  
Pros And Cons ◽  
Limited Supply ◽  
Evolutionary Consequences ◽  
Careful Assessment

The limited supply of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) raises the question of targeted vaccination. Many countries have opted to vaccinate older and more sensitive hosts first to minimize the disease burden. However, what are the evolutionary consequences of targeted vaccination? We clarify the consequences of different vaccination strategies through the analysis of the speed of viral adaptation measured as the rate of change of the frequency of a vaccine-adapted variant. We show that such a variant is expected to spread faster if vaccination targets individuals who are likely to be involved in a higher number of contacts. We also discuss the pros and cons of dose-sparing strategies. Because delaying the second dose increases the proportion of the population vaccinated with a single dose, this strategy can both speed up the spread of the vaccine-adapted variant and reduce the cumulative number of deaths. Hence, strategies that are most effective at slowing viral adaptation may not always be epidemiologically optimal. A careful assessment of both the epidemiological and evolutionary consequences of alternative vaccination strategies is required to determine which individuals should be vaccinated first.

scholarly journals Targeted vaccination and the speed of SARS-CoV-2 adaptation

2021 ◽  
Author(s):  
Sylvain Gandon ◽  
Sébastien Lion
Keyword(s):  
Vaccination Strategy ◽  
Rate Of Change ◽  
Escape Mutant ◽  
Slowing Down ◽  
Vaccination Strategies ◽  
Viral Adaptation ◽  
Vaccine Escape Mutant ◽  
Speed Up ◽  
Pros And Cons ◽  
Evolutionary Consequences

The limited supply of vaccines against SARS-CoV-2 raises the question of targeted vaccination. Older and more sensitive hosts should be vaccinated first to minimize the disease burden. But what are the evolutionary consequences of targeted vaccination? We clarify the consequences of different vaccination strategies through the analysis of the speed of viral adaptation measured as the rate of change of the frequency of vaccine-escape mutations. We show that a vaccine-escape mutant is expected to spread faster if vaccination targets individuals which are likely to be involved in a higher number of contacts. We also discuss the pros and cons of dose-sparing strategies. Because delaying the second dose increases the proportion of the population vaccinated with a single dose, this strategy can both speed-up the spread of the vaccine-escape mutant and reduce the cumulated number of deaths. Hence, slowing down viral adaptation may not always be the optimal vaccination strategy. We contend that a careful assessment of the consequences of alternative vaccination strategies on both (i) the speed of adaptation and (ii) the mortality is required to determine which individuals should be vaccinated first.

scholarly journals COVID-19: a review of current knowledge regarding exposure, quarantine, isolation and other preventive measures

2021 ◽  
Vol 8 ◽  
pp. 204993612110320
Author(s):  
Robert Rosolanka ◽  
Andres F. Henao-Martinez ◽  
Larissa Pisney ◽  
Carlos Franco-Paredes ◽  
Martin Krsak
Keyword(s):  
Immune Response ◽  
Severe Acute Respiratory Syndrome ◽  
Clinical Response ◽  
Preventive Measures ◽  
Current Knowledge ◽  
Therapeutic Options ◽  
Exposure Control ◽  
Knowledge Gaps ◽  
Vaccination Strategies ◽  
Speed Up

Deeper understanding of the spread, morbidity, fatality, and development of immune response associated with coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, is necessary in order to establish an appropriate epidemiological and clinical response. Exposure control represents a key part of the combat against COVID-19, as the effectiveness of current therapeutic options remains partial. Since the preventive measures have not been sufficiently able to slow down this pandemic, in this article we explore some of the pertinent knowledge gaps, while overall looking to effective vaccination strategies as a way out. Early on, such strategies may need to rely on counting the convalescents as protected in order to speed up the immunization of the whole population.

scholarly journals COVID-19: Mechanisms of Vaccination and Immunity

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 404 ◽  
Author(s):  
Daniel E. Speiser ◽  
Martin F. Bachmann
Keyword(s):  
Immune Responses ◽  
Clinical Management ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Public Life ◽  
High Affinity ◽  
Vaccination Strategies ◽  
Detailed Evaluation ◽  
Pros And Cons

Vaccines are needed to protect from SARS-CoV-2, the virus causing COVID-19. Vaccines that induce large quantities of high affinity virus-neutralizing antibodies may optimally prevent infection and avoid unfavorable effects. Vaccination trials require precise clinical management, complemented with detailed evaluation of safety and immune responses. Here, we review the pros and cons of available vaccine platforms and options to accelerate vaccine development towards the safe immunization of the world’s population against SARS-CoV-2. Favorable vaccines, used in well-designed vaccination strategies, may be critical for limiting harm and promoting trust and a long-term return to normal public life and economy.

Analyzing and Accelerating the Bottlenecks of Training Deep SNNs With Backpropagation

2020 ◽  
Vol 32 (12) ◽  
pp. 2557-2600
Author(s):  
Ruizhi Chen ◽  
Ling Li
Keyword(s):  
Neural Networks ◽  
Training Algorithms ◽  
Minimization Method ◽  
Data Set ◽  
Ultra Low Power ◽  
Training Performance ◽  
Speed Up ◽  
Pros And Cons ◽  
Accuracy Increase ◽  
Initialization Algorithm

Spiking neural networks (SNNs) with the event-driven manner of transmitting spikes consume ultra-low power on neuromorphic chips. However, training deep SNNs is still challenging compared to convolutional neural networks (CNNs). The SNN training algorithms have not achieved the same performance as CNNs. In this letter, we aim to understand the intrinsic limitations of SNN training to design better algorithms. First, the pros and cons of typical SNN training algorithms are analyzed. Then it is found that the spatiotemporal backpropagation algorithm (STBP) has potential in training deep SNNs due to its simplicity and fast convergence. Later, the main bottlenecks of the STBP algorithm are analyzed, and three conditions for training deep SNNs with the STBP algorithm are derived. By analyzing the connection between CNNs and SNNs, we propose a weight initialization algorithm to satisfy the three conditions. Moreover, we propose an error minimization method and a modified loss function to further improve the training performance. Experimental results show that the proposed method achieves 91.53% accuracy on the CIFAR10 data set with 1% accuracy increase over the STBP algorithm and decreases the training epochs on the MNIST data set to 15 epochs (over 13 times speed-up compared to the STBP algorithm). The proposed method also decreases classification latency by over 25 times compared to the CNN-SNN conversion algorithms. In addition, the proposed method works robustly for very deep SNNs, while the STBP algorithm fails in a 19-layer SNN.

Principles of wound care

2018 ◽  
pp. 105-114
Author(s):  
Abdullah Jibawi ◽  
Mohamed Baguneid ◽  
Arnab Bhowmick
Keyword(s):  
Wound Care ◽  
Healing Process ◽  
Cost Effective ◽  
Control Measures ◽  
Foot Care ◽  
Nice Guidelines ◽  
Infection Control Measures ◽  
Speed Up ◽  
Careful Assessment

It’s important to be aware of healing process, associated comorbidities, and the role of nutrition in wound care management. Assessment of the amount and type of wound exudate plays an important role in deciding the type of dressing used. Infection or underlying osteomyelitis needs careful assessment, further investigation, and administration of systemic/oral anti-microbial therapy. Early use of non-surgical or surgical debridement is necessary to speed up the healing process. Diagnostic criteria of surgical site infection are increasingly used in postoperative wounds in hospitals for audit of infection control measures. No one type of dressing appears superior over other. Dressings should be cost effective, acceptable to the patients, and easy to use. In addition, in recent decades newer non-surgical debriding method, e.g. larvae therapy and negative pressure wound therapy, are increasingly being used and supported by recent NICE guidelines, especially in diabetic foot care.

Technology and Disabilities in the Century Ahead

2011 ◽  
pp. 2077-2081
Author(s):  
Ray Kurzweil
Keyword(s):  
20Th Century ◽  
21St Century ◽  
Current Level ◽  
Rate Of Change ◽  
The World ◽  
The Future ◽  
The Disabled ◽  
Speed Up ◽  
Technology Trends ◽  
Over Time

I have been involved in inventing since I was five, and I quickly realized that for an invention to succeed, you have to target the world of the future. But what would the future be like? To find out, I became a student of technology trends and began to develop mathematical models of different technologies: computation, miniaturization, evolution over time. I have been doing that for 25 years, and it has been remarkable to me how powerful and predictive these models are. Now, before I show you some of these models and then try to build with you some of the scenarios for the future—and, in particular, focus on how these will benefit technology for the disabled—I would like to share one trend that I think is particularly profound and that many people fail to take into consideration. It is this: the rate of progress—what I call the “paradigmshift rate”—is itself accelerating. We are doubling this paradigm-shift rate every decade. The whole 20th century was not 100 years of progress as we know it today, because it has taken us a while to speed up to the current level of progress. The 20t h century represented about 20 years of progress in terms of today’s rate. And at today’s rate of change, we will achieve an amount of progress equivalent to that of the whole 20th century in 14 years, then as the acceleration continues, in 7 years. The progress in the 21st century will be about 1,000 times greater than that in the 20th century, which was no slouch in terms of change.

scholarly journals The impact of the newly licensed dengue vaccine in endemic countries

2016 ◽  
Author(s):  
M. Aguiar ◽  
Nico Stollenwerk ◽  
Scott B. Halstead
Keyword(s):  
Disease Burden ◽  
Phase Iii ◽  
World Health ◽  
Severe Dengue ◽  
Dengue Vaccine ◽  
Endemic Region ◽  
Dengue Disease ◽  
Vaccination Strategies ◽  
Tetravalent Vaccine ◽  
The Impact

AbstractBackground:With approximately 3 billion people at risk of acquiring the infection, dengue fever is now considered the most important mosquito-borne viral disease in the world, with 390 million dengue infections occurring every year, of which 96 million manifest symptoms with any level of disease severity. Treatment of uncomplicated dengue cases is only supportive and severe dengue cases require hospital intensive care. A vaccine now licensed in several countries and developed by Sanofi Pasteur (CYD-TDV, named Dengvaxia), is able to protect, in the first 25 months of the two Phase III, 66% of a subset of 9 − 16 year old participants. However, a significantly lower efficacy (including negative vaccine efficacy) was noted for children younger than 9 years of age.Methodology/Principal Findings:Analysis of year 3 results of phase III trials of Dengvaxia suggest high rates of protection of vaccinated partial dengue immunes but high rates of hospitalizations during breakthrough dengue infections of persons who were vaccinated when seronegative, with vaccine appearing to induce enhancing antibodies (ADE). An age structured model was developed based on Sanofi’s recommendation to vaccinate persons age 945 years in dengue endemic countries. The model was used to explore the clinical burden of two vaccination strategies: 1) Vaccinate 4 or 20% of individuals, ages 9 − 45 years, seropositives and seronegatives, and 2) vaccinate 4 or 20% of individuals, ages 9 − 45 years, who are dengue immune only.Conclusions/Significance:Our results show that vaccinating dengue monotypic immune individuals prevents dengue hospitalizations, but at the same time dengue infections of vaccine-sensitized persons increases hospitalizations. When the vaccine is given only to partial immune individuals, after immuno-logical screening of the population, disease burden decreases considerably.Author SummaryCaused by four antigenically related but distinct serotypes a tetravalent vaccine is needed to protect against the huge burden of dengue disease. Dengvaxia is a vaccine candidate now licensed in several countries for individuals 9 − 45 years of age living in endemic countries with least 70% of seroprevalence. Modelers from Sanofi Pasteur have predicted that this vaccine has the potential to reduce by about 50% the disease burden within 5 years when 20% of an endemic country population is vaccinated, thus achieving a World Health Organization dengue prevention goal.In this paper, mathematical modeling is used to investigate the impact of the newly licensed dengue vaccine using different scenarios. Our results show that to achieve significant reduction in disease bur-den, the vaccination program is most effective if it includes only individuals that have been already exposed to at least one dengue virus. Immunological screening of the population prior to vaccination is advised and vaccination strategies must be planned based on epidemiological disease dynamics for each specific endemic region.

scholarly journals Synergistic coevolution accelerates genome evolution

2021 ◽  
Author(s):  
Daniel Preussger ◽  
Alexander Herbig ◽  
Christian Kost
Keyword(s):  
Molecular Evolution ◽  
Rapid Evolution ◽  
Ecological Interactions ◽  
Metabolic Cooperation ◽  
Interacting Species ◽  
Long Run ◽  
Speed Up ◽  
Key Drivers ◽  
Evolutionary Consequences ◽  
Rapid Emergence

Ecological interactions are key drivers of evolutionary change. Although it is welldocumented that antagonistic coevolution can accelerate molecular evolution, the evolutionary consequences of synergistic coevolution remain poorly understood. Here we show experimentally that also synergistic coevolution can speed up the rate of molecular evolution. Pairs of auxotrophic genotypes of the bacterium Escherichia coli, whose growth depended on a reciprocal exchange of amino acids, were experimentally coevolved, and compared to two control groups of independently growing cells. Coevolution drove the rapid emergence of a strong metabolic cooperation that correlated with a significantly increased number of mutations in coevolved auxotrophs as compared to monoculture controls. These results demonstrate that synergistic coevolution can cause rapid evolution that in the long run may drive diversification of mutualistically interacting species.

scholarly journals 1389. Economic Evaluation of Universal Varicella Vaccination in Mexico

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S704-S704
Author(s):  
Enrique Chacon-Cruz ◽  
Estelle Meroc ◽  
Sue Ann Costa-Clemens ◽  
Thomas Verstraeten
Keyword(s):  
Cost Effectiveness ◽  
Cost Saving ◽  
Economic Burden ◽  
Disease Burden ◽  
Varicella Vaccine ◽  
Cost Effective ◽  
Varicella Vaccination ◽  
Published Data ◽  
Vaccination Strategies ◽  
The Impact

Abstract Background Universal varicella vaccination (UVV) has proven to be cost-effective in countries where implemented. However, this has not yet been evaluated for Mexico. We assessed the cost-effectiveness of UVV in the Mexican Immunization Program from both healthcare and societal perspectives. Methods The annual disease burden (varicella cases/deaths, outpatient visits, and hospitalizations) were derived from Mexican seroprevalence-published data adjusted to the 2020 country’s population. The annual economic burden was calculated by combining disease with Mexican published unit cost data. Four different vaccination strategies were evaluated: 1. One dose of a single varicella vaccine at 1 year old; 2. Two doses of single varicella vaccine at 1 and 6 years; 3. One dose of a single varicella vaccine at 1 year, and quadrivalent measles-mumps-rubella-varicella vaccine (MMRV) at 6 years; 4. Two doses of MMRV at 1 and 6 years. We developed an economic model for each vaccination strategy where 20 consecutive birth cohorts were simulated. The impact of vaccination (number of avoided cases/deaths) was evaluated for a 20 years follow-up period based on vaccine effectiveness (87% and 97.4%), and assuming a 95% coverage. Subsequently, we estimated net vaccination costs, benefit-cost ratio (BCR), annual costs saved, cost-effectiveness ratio. Results From annual disease burden estimation, avoided cases with one dose, and two doses were of 20,570,722 and 23,029,751, respectively. From the 20 years cohort, the yearly number of varicella cases was estimated at 2,041,296, and total costs at $115,565,315 (USD) (healthcare perspective) and $165,372,061 (healthcare and societal perspectives). Strategies 1 and 2 were found to be cost-saving (BCR >1) (Figure 1), and strategy 3 to be cost-effective (CE) ($1539 per Life Year Gained). Strategy 4 was not CE. Strategies 1 and 2 would allow saving annually $53.16 million and $34.41 million, respectively, to the Mexican society. FIGURE 1 Conclusion 1.The disease and economic burden of varicella in Mexico are high. 2.UVV with four different vaccination strategies results in a high reduction of cases. 3.From healthcare and societal perspectives, UVV was shown to be cost-effective (with strategy 3), and cost-saving (with strategies using one dose or two doses separately). Disclosures All Authors: No reported disclosures

▾ Securon SR: sustained-release verapamil

1987 ◽  
Vol 25 (12) ◽  
pp. 47-48
Keyword(s):  
Blood Pressure ◽  
Sustained Release ◽  
Cardiac Arrhythmias ◽  
Moderate Hypertension ◽  
Clinical Use ◽  
Lower Blood Pressure ◽  
Lower Blood ◽  
Sustained Release Verapamil ◽  
Pros And Cons ◽  
Careful Assessment

Verapamil was the first calcium antagonist in clinical use and its value in the treatment of angina, hypertension and cardiac arrhythmias is well established.1 Standard verapamil tablets have to be taken twice or three times daily but now a scored sustained-release (s/r) tablet containing 240mg verapamil (Securon SR - Knoll) has been licensed for the treatment of mild to moderate hypertension. A single dose is claimed to lower blood pressure for 24 hours. As we have noted before,2 the pros and cons of s/r products need careful assessment.

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