scholarly journals Vaccinating in disease-free regions: a vaccine model with application to yellow fever

2007 ◽  
Vol 4 (17) ◽  
pp. 1119-1125 ◽  
Author(s):  
Claudia T Codeço ◽  
Paula M Luz ◽  
Flavio Coelho ◽  
Alison P Galvani ◽  
Claudio Struchiner
Keyword(s):  
Yellow Fever ◽  
Ethical Issues ◽  
Disease Risk ◽  
Nonlinear Dependence ◽  
Vaccination Strategies ◽  
Control Programmes ◽  
Vaccination Decision ◽  
Pros And Cons ◽  
Serious Disease ◽  
Disease Free

Concerns regarding natural or induced emergence of infectious diseases have raised a debate on the pros and cons of pre-emptive vaccination of populations under uncertain risk. In the absence of immediate risk, ethical issues arise because even smaller risks associated with the vaccine are greater than the immediate disease risk (which is zero). The model proposed here seeks to formalize the vaccination decision process looking from the perspective of the susceptible individual, and results are shown in the context of the emergence of urban yellow fever in Brazil. The model decomposes the individual's choice about vaccinating or not into uncertain components. The choice is modelled as a function of (i) the risk of a vaccine adverse event, (ii) the risk of an outbreak and (iii) the probability of receiving the vaccine or escaping serious disease given an outbreak. Additionally, we explore how this decision varies as a function of mass vaccination strategies of varying efficiency. If disease is considered possible but unlikely (risk of outbreak less than 0.1), delay vaccination is a good strategy if a reasonably efficient campaign is expected. The advantage of waiting increases as the rate of transmission is reduced (low R 0 ) suggesting that vector control programmes and emergency vaccination preparedness work together to favour this strategy. The opposing strategy, vaccinating pre-emptively, is favoured if the probability of yellow fever urbanization is high or if expected R 0 is high and emergency action is expected to be slow. In summary, our model highlights the nonlinear dependence of an individual's best strategy on the preparedness of a response to a yellow fever outbreak or other emergent infectious disease.

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.

Incorporation of Posttransplant Cyclophosphamide (PCy) As Part of Standard Immunoprophylaxis (IP) for All Allogeneic Transplants: A Retrospective, Single Institution Study

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4485-4485
Author(s):  
Dennis Cooper ◽  
Jackie Manago ◽  
Vimal Patel ◽  
Dale Schaar ◽  
Tracy Krimmel ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Transplantation ◽  
Disease Risk ◽  
Conflicts Of Interest ◽  
Risk Index ◽  
Chronic Gvhd ◽  
Number Of Patients ◽  
One Year ◽  
Disease Free

Background: The incorporation of PCy in IP has allowed transplantation of stem cells from haploidentical (HI) family members such that nearly all patients have a potential donor. Thus far, HI stem cell transplantation with PCy appears to yield comparable results to matched unrelated (MUD) and matched sibling donors (MSD) who have been treated with conventional GVHD regimens, but with less chronic GVHD (cGVHD). Particularly in light of the low incidence of cGVHD, which has not been achieved with other IP strategies after T cell-replete products, PCy is being investigated after MUD and MSD transplantation where complications from cGVHD remain the major cause of non-relapse mortality. A recent study from the BMTCTN showed that in patients conditioned with reduced intensity regimens and who received MSD and MUD stem cells, the addition of PCy to standard IP (SIP) was superior to either bortezomib or maravoric in the composite endpoint of graft-versus-host disease-free, relapse-free survival (GRFS). However, this study did not include patients who received ablative conditioning regimens and did not report on the percentage of patients who were disease-free and off immunosuppression (DFOI) at 1 year after transplant. In the present study, we have compared our experience with the addition of PCy for essentially all allogeneic stem cell transplants treated over a 2 year period with the results of patients treated with SIP in the prior two year span. Outcomes of interest included one-year overall survival (OS) and one-year GRFS as well as the percentage of patients DFOI at one year. Methods: With the exception of patients receiving umbilical cord blood transplants, beginning in April 2016, all but two patients who received allogeneic transplants were given mobilized peripheral blood stem cells and then treated with PCy on days +3 and +4 followed by tacrolimus and mycophenolate on day 5. In the absence of GVHD, mycophenolate was stopped at days +35-50 and tacrolimus was tapered beginning after day +100 unless there was low donor chimerism or a suspicion of relapse in which case tacrolimus could be tapered sooner. In order to have at least one-year follow-up, the last patient included in the study was treated before April 2018. During this time period, MSD were prioritized over MUD which in turn were chosen over haploidentical donors. For comparison, we looked at the prior 2 year period (2014-2016) in which patients were treated with SIP (including ATG in patients who received MUD stem cells). Because of a higher percentage of patients with an advanced disease risk index (DRI) in the years 2014-2016, we restricted our analysis in the SIP cohort to those patients with low and intermediate risk disease but included all patients in the more recent period who received PCy. Results: There were 68 patients treated in the PCy group, including 2 patients who received PCy after HI transplants in the years 2014 and 2015. After eliminating patients with high DRI there were 40 patients in the earlier SIP cohort of patients. The resulting patient groups were similar with respect to median age (53) and diagnosis (approximately 80% of patients with AML and ALL). There was a slightly higher percentage of patients in the SIP group with hematopoietic cell transplantation-comorbidity index scores of 3 or more (52.5 vs 48.5). In the PCy group the number of patients with early, intermediate and advanced DRI were 2, 53 and 13, whereas in the (modified) SIP category 2 patients had a low DRI and 38 had intermediate DRI. In the PCy group, HI donors comprised 26.5% of the total compared to 19.1% MSD and 54.4% MUD donors. In the SIP group, MSD and MUD donors accounted for 30% and 70% of the donors. One-year percentages of OS, GRFS and DFOI were 79.4, 47.1 and 44.1 in the PCy group compared to 72, 45 and 35 in the SIP cohort. If the analysis of the PCy group is limited to the 50 patients with MSD and MUD donors (as in the SIP cohort), the one-year OS, GRFS and DFOI are 88, 52 and 52. Conclusions: PCy in combination with SIP resulted in at least comparable results as SIP despite the inclusion of 19% of patients with a high DRI and 26.5% HI donors. The results with the addition of PCy are excellent in patients with MSD and MUD donors with more than half of the patients GRFS and DFOI at one year. Future studies on GVHD prophylaxis should report DFOI as the latter status may be the best platform for posttransplant strategies aimed at eliminating minimal residual disease and for improving QOL. Disclosures No relevant conflicts of interest to declare.

Animal Disease Epidemics: Implications for Production, Policy and Trade

2002 ◽  
Vol 31 (3) ◽  
pp. 151-160 ◽  
Author(s):  
Alison Burrell
Keyword(s):  
Ethical Issues ◽  
Private Insurance ◽  
Animal Disease ◽  
Policy Makers ◽  
Production Policy ◽  
Contingency Plans ◽  
Social And Ethical Issues ◽  
The Cost ◽  
Disease Epidemics ◽  
Disease Free

The outbreak of a highly infectious animal disease in a disease-free area is an ever-present risk. Recent epidemics in European livestock populations illustrate that the cost in terms of eradication, lost production and trade disruption may be high. In this paper, the implications for the meat and livestock industry, government policy and international trade rules are considered. The need for strict biosecurity and effective contingency plans is stressed. Options such as private insurance, animal tracing systems and emergency vaccination are discussed. Current measures for controlling animal disease epidemics raise various social and ethical issues that complicate the policy makers' task.

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 Prenatal and Preimplantation Genetic Diagnosis of Huntington's Disease

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Joep P.M. Geraedts ◽  
Keyword(s):  
At Risk ◽  
Genetic Testing ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Preimplantation Genetic Diagnosis ◽  
Genetic Diagnosis ◽  
Preimplantation Genetic Testing ◽  
Dominant Disease ◽  
Pros And Cons ◽  
Disease Free

Huntington’s disease (HD) is an autosomal dominant disease that immensely impacts the affected families. However, the transmission of the disease from carriers to their offspring could be prevented. Prenatal diagnosis (PND) and preimplantation genetic diagnosis (PGD) are the only two available reproductive options for the carriers at risk to have disease-free children. PND for HD could be done through two kinds of genetic testing: direct and indirect. The same approaches are available for preimplantation genetic testing. In addition, a third alternative is nondisclosure testing, which is only available in the case of PGD. The pros and cons of different approaches are discussed. However, only a relatively few at-risk parents opt for PND and PGD. Furthermore, compared to PND, PGD is even more seldom opted for as a reproductive option.

scholarly journals The estimation of health state utility values in rare diseases: overview of existing techniques

2020 ◽  
Vol 36 (5) ◽  
pp. 469-473
Author(s):  
Michela Meregaglia ◽  
Elena Nicod ◽  
Michael Drummond
Keyword(s):  
Rare Diseases ◽  
Ethical Issues ◽  
Health State Utility ◽  
Health State ◽  
Health States ◽  
Promising Alternative ◽  
Utility Values ◽  
Life Threatening ◽  
Pros And Cons ◽  
Health State Utility Values

There are several techniques for estimating health state utility values, each of which presents pros and cons in the context of rare diseases (RDs). Direct approaches (e.g. standard gamble and time trade-off) may be too demanding for patients with RDs, since most of them affect young children or cause cognitive impairment. The alternatives are using “vignettes” that describe hypothetical health states for the general public, which may not reflect the heterogeneous manifestations of RDs, or multi-attribute utility instruments (i.e. indirect techniques), such as EQ-5D, which may be less sensitive in capturing the specificities of RDs. The “rule of rescue” approach is a promising alternative in RDs, since it prioritizes identifiable patients with life-threatening or disabling conditions. However, it raises measurement challenges and ethical issues. Furthermore, the literature reports on relevant implications of choosing a technique over others for health technology assessment, which should be considered in relation to individual RDs.

scholarly journals Risiko Impfen?

2019 ◽  
Vol 144 (04) ◽  
pp. 254-261
Author(s):  
Frank Kowalzik ◽  
Fred Zepp
Keyword(s):  
Political Institutions ◽  
Disease Risk ◽  
Family Physicians ◽  
Subjective Perception ◽  
Decision Confidence ◽  
Individual Perception ◽  
Vaccination Recommendations ◽  
Vaccination Decision ◽  
Almost All ◽  
Individual Disease

AbstractSkepticism about vaccination is not new, but the perception of vaccine-related risks has changed in recent decades. In addition to aspects such as knowledge about vaccines, trust in medical care structures and political institutions, socio-economic, cultural and religious views also play an important role. These factors differ significantly worldwide and regionally. In almost all surveys, confidence in vaccines and/or the healthcare system is identified as essential for a positive vaccination decision. Confidence in vaccines correlates with the assessment of the specific individual disease risk and the potential side effects of the vaccines. Subjective perception of risk seldom corresponds to objectively measurable facts. Rather, it is distorted by individual perception in both directions (underestimation and overestimation). Transparent, science-based communication is helpful in promoting and maintaining trust in healthcare. Pediatricians and family physicians are the most important confidants for parents on questions about health care and vaccination recommendations.

scholarly journals Equilibrium Analysis of a Yellow Fever Dynamical Model with Vaccination

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Silvia Martorano Raimundo ◽  
Marcos Amaku ◽  
Eduardo Massad
Keyword(s):  
Mortality Rate ◽  
Yellow Fever ◽  
Human Population ◽  
Reproduction Number ◽  
Vaccination Rate ◽  
Equilibrium Analysis ◽  
Dynamical Model ◽  
Disease Dynamics ◽  
Vaccination Strategies ◽  
Over Time

We propose an equilibrium analysis of a dynamical model of yellow fever transmission in the presence of a vaccine. The model considers both human and vector populations. We found thresholds parameters that affect the development of the disease and the infectious status of the human population in the presence of a vaccine whose protection may wane over time. In particular, we derived a threshold vaccination rate, above which the disease would be eradicated from the human population. We show that if the mortality rate of the mosquitoes is greater than a given threshold, then the disease is naturally (without intervention) eradicated from the population. In contrast, if the mortality rate of the mosquitoes is less than that threshold, then the disease is eradicated from the populations only when the growing rate of humans is less than another threshold; otherwise, the disease is eradicated only if the reproduction number of the infection after vaccination is less than 1. When this reproduction number is greater than 1, the disease will be eradicated from the human population if the vaccination rate is greater than a given threshold; otherwise, the disease will establish itself among humans, reaching a stable endemic equilibrium. The analysis presented in this paper can be useful, both to the better understanding of the disease dynamics and also for the planning of vaccination strategies.

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